Car sluggish, have theories, need help to diagnose
04-14-09, 01:37 PM
#1
Car sluggish, have theories, need help to diagnose. UPDATED - FIXED
*****************************************************************************
CAR IS FIXED. AS A MATTER OF FACT, I DON'T REMEMBER IT BEING THIS QUICK BEFORE. QUICK RECAP.
1. SRT INTAKE ECU BLOCKED CHECK ENGINE CODES
2, SRT INTAKE ECU OUT, CAR BARELY RUNS
3. MAF SENSOR, ECT SENSOR, PCV VALVE, FUEL FILTER ARE THE PARTS I REPLACED.
4. BUNCH OF BEERS THROUGHOUT THE PROCESS.
******************************************************************************
I need your guys help. My GS430 is now kind of dangerous to drive.
Whenever I hit the gas, stand-still, moving any time I want some performance, first my car bogs down, then takes off. So if I need to get through traffic briskly, I cannot, the car really does not respond properly.
When the light turns green, I press the gas pedal anything more than grandma, and my car bogs for a good half a sec, then takes off.
When I straight up floor it, my car bogs, then pops like its backfiring, then takes off.
I also seem to have a loss in performance above 4k RPS.
My Theory to the cause of all this.
1. I have a feeling my Cats are toast. I haven't confirmed it because I don't have any codes. I get the rotten egg smell after aggressive driving, but I think that is ok since I drove new Lexus cars, and they all do that. But I get the popping noise, so I am leaning to them being messed up.
2. Can the accelerator pedal position switch be causing this as well? Like I said, I don't have any codes, so I don't even know how to diagnose this at all.
I have 120k miles, so factory warrantee on the Cats is out. I have a borla cat back, and SRT intake. I don't think either will cause my symptoms.
Please help me with this before I waste money buying parts I don't need. This is just driving me nuts, and even though I need to finish my house, I am willing to drop everything to fix this. Thanks to all in advance.
CAR IS FIXED. AS A MATTER OF FACT, I DON'T REMEMBER IT BEING THIS QUICK BEFORE. QUICK RECAP.
1. SRT INTAKE ECU BLOCKED CHECK ENGINE CODES
2, SRT INTAKE ECU OUT, CAR BARELY RUNS
3. MAF SENSOR, ECT SENSOR, PCV VALVE, FUEL FILTER ARE THE PARTS I REPLACED.
4. BUNCH OF BEERS THROUGHOUT THE PROCESS.
******************************************************************************
I need your guys help. My GS430 is now kind of dangerous to drive.
Whenever I hit the gas, stand-still, moving any time I want some performance, first my car bogs down, then takes off. So if I need to get through traffic briskly, I cannot, the car really does not respond properly.
When the light turns green, I press the gas pedal anything more than grandma, and my car bogs for a good half a sec, then takes off.
When I straight up floor it, my car bogs, then pops like its backfiring, then takes off.
I also seem to have a loss in performance above 4k RPS.
My Theory to the cause of all this.
1. I have a feeling my Cats are toast. I haven't confirmed it because I don't have any codes. I get the rotten egg smell after aggressive driving, but I think that is ok since I drove new Lexus cars, and they all do that. But I get the popping noise, so I am leaning to them being messed up.
2. Can the accelerator pedal position switch be causing this as well? Like I said, I don't have any codes, so I don't even know how to diagnose this at all.
I have 120k miles, so factory warrantee on the Cats is out. I have a borla cat back, and SRT intake. I don't think either will cause my symptoms.
Please help me with this before I waste money buying parts I don't need. This is just driving me nuts, and even though I need to finish my house, I am willing to drop everything to fix this. Thanks to all in advance.
Last edited by slickgt1; 05-08-09 at 06:06 AM. Reason: Car is fixed.
04-14-09, 02:06 PM
#2
Try just doing some simple (cheap) maintenance first. Even if you don't think it applies, it is almost throw-away money as compared to parts.
-Run through a tank with a high concentration of Fuel Additive(e.g. amsoil or redline), gas perhaps from a different gasoline station then your usual.
-do an oil change/diff/tranny drain and fill. Try auto-rx perhaps for your oil.
-change air filter, clean MAF and Throttlebody (carefully)
-perhaps seafoam
-after all of that reset ECU, drive around for a week, see if any improvement.
If it's still no good, perhaps then start thinking about spending more money for more serious solutions.
-Run through a tank with a high concentration of Fuel Additive(e.g. amsoil or redline), gas perhaps from a different gasoline station then your usual.
-do an oil change/diff/tranny drain and fill. Try auto-rx perhaps for your oil.
-change air filter, clean MAF and Throttlebody (carefully)
-perhaps seafoam
-after all of that reset ECU, drive around for a week, see if any improvement.
If it's still no good, perhaps then start thinking about spending more money for more serious solutions.
Last edited by raytseng; 04-14-09 at 02:43 PM.
04-14-09, 02:15 PM
#3
You get the rotten egg smell because your car is running rich, not because your cats are clogged. Now you are running rich because either your air/fuel ratio is not correct, or your your ignition system isnt working properly. Also it could be that your throttle system isnt working right.
In regards to the ignition system, have you dont a tune up recently? Replace spark plugs, pcv valve, air filter. If you're still running on the originals, its very past due.
As far as the throttle system, check your TPS, and have your throttle body cleaned. Do a seafoam threatment or opt for one of these "runrite" services that your local repair shops offer.
As far as the air/fuel ratio, it could be a number of things - your ECU, you engine coolant temp sensor, your O2 sensors or your MAF sensor. I see you're running SRT intake, I believe those come with K&N type filter? Sometimes the oil from the filter gets onto the MAF and fouls it, it sends wrong reading to the ECU and it in turn makes wrong adjustments to the A/F ratio. Start by cleaning your MAF with proper CRC electronics/maf cleaner.
Also run a can of BG44K or Chevron Techron fuel system cleaner through your gastank. Don't use anything besides these two, because the rest is usually useless crap in pretty bottles.
In regards to the ignition system, have you dont a tune up recently? Replace spark plugs, pcv valve, air filter. If you're still running on the originals, its very past due.
As far as the throttle system, check your TPS, and have your throttle body cleaned. Do a seafoam threatment or opt for one of these "runrite" services that your local repair shops offer.
As far as the air/fuel ratio, it could be a number of things - your ECU, you engine coolant temp sensor, your O2 sensors or your MAF sensor. I see you're running SRT intake, I believe those come with K&N type filter? Sometimes the oil from the filter gets onto the MAF and fouls it, it sends wrong reading to the ECU and it in turn makes wrong adjustments to the A/F ratio. Start by cleaning your MAF with proper CRC electronics/maf cleaner.
Also run a can of BG44K or Chevron Techron fuel system cleaner through your gastank. Don't use anything besides these two, because the rest is usually useless crap in pretty bottles.
04-14-09, 03:49 PM
#5
Your car has an electronic control throttle. Do NOT clean it. You will regret it. The is running sluggish is most likely because of the SRT intake. Take it off and disconnect your battery and see any difference. And if the MAF is dirty, then do use the MAF cleaner. GL!
04-14-09, 11:33 PM
#7
Master Thread Closer!!
iTrader: (33)
Join Date: Jul 2002
Location: Waipahu, Waikele, HI
Posts: 9,859
Likes: 0
Received 9 Likes
on
9 Posts
It could be a number of problems.
Check your MAF sensor....is it gunked up? Clean it. Check and clean your throttlebody as well. The butterfly may be stuck if gunked up. Possible reason for the gunk is too much oil from the cone intake filter.
Use premium gas....Shell Vpower or Chevron with Techron.
Add some fuel injector cleaner to your gas....injectors may be dirty.
Double check sparkplug wires...make sure its secured.
SRT intake and race ECU. I had a similar issue long ago. Removed it...and installed the stock setup to debug the problem....sure enough....the problem was gone after removing SRT and race ECU. Do it...and reset your ECU for a few hours.
Good luck.
Pete
Check your MAF sensor....is it gunked up? Clean it. Check and clean your throttlebody as well. The butterfly may be stuck if gunked up. Possible reason for the gunk is too much oil from the cone intake filter.
Use premium gas....Shell Vpower or Chevron with Techron.
Add some fuel injector cleaner to your gas....injectors may be dirty.
Double check sparkplug wires...make sure its secured.
SRT intake and race ECU. I had a similar issue long ago. Removed it...and installed the stock setup to debug the problem....sure enough....the problem was gone after removing SRT and race ECU. Do it...and reset your ECU for a few hours.
Good luck.
Pete
Last edited by PHML; 04-15-09 at 01:26 AM.
Trending Topics
04-17-09, 06:28 AM
#10
Thanks for all the replies. Here are the things I have done as far as maintenance on my car.
1. Plugs I changed them about 2k miles ago. I though it was something with my plugs but no nothing changed. I checked the coil connectors everything is fine. Remember the car idles fine, runs fine, as long as I don't press the gas pedal harder than a fly could. Once moving, the car runs pretty much fine, until I floor it, then it backfires, downshifts, and starts to haul ***, but not the same after 4k rpm. Seems to die out after 4k rpm.
2. I do a tranny oil drain and fill every time I do my oil change. Diff fluid twice a year. Checked the oil levels just now, everything ok, and smells fine. Color is still clear on the oil (about 500 miles since change), tranny oil looks red, smells like fluid, not burnt.
3. I run fuel injection cleaner about once a month. I will try to get the BG44k or the Chevron stuff tonight, I never used that before. I used Lucas injector cleaner though.
4. I have the SRT ecu + intake. Had it for about 3 years, problem started about 5-7 months ago. I also changed out the air filter about 2 months ago to an AEM non-oiled one. Didn't clean the maf when doing that, I will give it a try.
5. I have reset the damn ecu a million times. I did it with the scan tool, and by unplugging the battery. Nothing changed at all.
6. Where is the PCV valve on the GS430? I can change that, don't know where it is.
7. How do I change the fuel filter? I was under the impression that ours is lifetime, and really hard to get to.
*** recap of what I need to do.
a. I will run different injector cleaner.
b. I will clean my MAF and TB tonight.
c. Need help to find out where the PCV valve is, and I will order it.
d. Fuel filter, don’t know this can be done at all. I was under the impression the car is running rich, not starving, but if it can be changed, I can do it.
Thanks all, please keep the suggestions comming.
1. Plugs I changed them about 2k miles ago. I though it was something with my plugs but no nothing changed. I checked the coil connectors everything is fine. Remember the car idles fine, runs fine, as long as I don't press the gas pedal harder than a fly could. Once moving, the car runs pretty much fine, until I floor it, then it backfires, downshifts, and starts to haul ***, but not the same after 4k rpm. Seems to die out after 4k rpm.
2. I do a tranny oil drain and fill every time I do my oil change. Diff fluid twice a year. Checked the oil levels just now, everything ok, and smells fine. Color is still clear on the oil (about 500 miles since change), tranny oil looks red, smells like fluid, not burnt.
3. I run fuel injection cleaner about once a month. I will try to get the BG44k or the Chevron stuff tonight, I never used that before. I used Lucas injector cleaner though.
4. I have the SRT ecu + intake. Had it for about 3 years, problem started about 5-7 months ago. I also changed out the air filter about 2 months ago to an AEM non-oiled one. Didn't clean the maf when doing that, I will give it a try.
5. I have reset the damn ecu a million times. I did it with the scan tool, and by unplugging the battery. Nothing changed at all.
6. Where is the PCV valve on the GS430? I can change that, don't know where it is.
7. How do I change the fuel filter? I was under the impression that ours is lifetime, and really hard to get to.
*** recap of what I need to do.
a. I will run different injector cleaner.
b. I will clean my MAF and TB tonight.
c. Need help to find out where the PCV valve is, and I will order it.
d. Fuel filter, don’t know this can be done at all. I was under the impression the car is running rich, not starving, but if it can be changed, I can do it.
Thanks all, please keep the suggestions comming.
04-17-09, 06:38 AM
#11
*********UPDATE**********
My co-worker and I just went outside and he revved my car while I got low to the floor to listen to it. It sounds like I may have things rolling in by exhaust. I can't pinpoint where it’s coming from. But will get on ramps tomorrow and check it out.
My co-worker and I just went outside and he revved my car while I got low to the floor to listen to it. It sounds like I may have things rolling in by exhaust. I can't pinpoint where it’s coming from. But will get on ramps tomorrow and check it out.
04-17-09, 06:47 AM
#12
Accelerates slowly then OK until 3K rpm then it bogs sometimes I hear a bang/clunk under the car then it pulls through 3K though not as powerful as before.
Pulled a "too lean code" on both banks a few weeks ago P0171 & P0174.
Cat's stank on Full Throttle for a while but not so much anymore, probably because I'm not pushing FT with the cats being plugged.
Any way I'll be putting some of my tax refund into replacing the cats but I don't know which kind to buy and I can't find that info here on CL. I'm guessing that 2.5" inlet/outlet 13" OAL will work but do I need 2 or 3 element cats, I dunno.
DaveC
Last edited by BossGS4; 04-17-09 at 07:39 AM.
04-17-09, 07:05 AM
#13
It's funny because after reading this thread I always felt I had issues with my cats too! I was always getting CEL's on my dash and the car always felt sluggish...so I forced it to not feel sluggish by adding all my mods; I too could have a problem. My car is 9yrs old with almost 110K mi. in any event my cats I'm sure are NOT up to 100% efficiency and it could ONLY yield positivity by changing them out. Just before I replaced all my O2 sensors (if the rear ones are bad for a long time this could ruin your cats as well) I was getting a PO430 code (catalytic inefficiency)...so perhaps changing the O2's "masked" the underlying cat issue.
Slick - I would definitly change out your cats..especially if your actually hearing something rolling around in there. Oh, and perform all the maint. that everyone mentioned earlier in this thread. GL!
Slick - I would definitly change out your cats..especially if your actually hearing something rolling around in there. Oh, and perform all the maint. that everyone mentioned earlier in this thread. GL!
04-17-09, 07:40 AM
#14
Rock-a-Lex
Yea I have a feeling I'm heading in that direction as well. The only problem I have with this, is that I am not getting any codes at all. I really don't understand how this can be. The only thing I can think of is that all the oxygen sensors are bad, and the car is thinking everything is ok.
Did you change your cats out? Did you go stock or magnaflow? Thanks.
Yea I have a feeling I'm heading in that direction as well. The only problem I have with this, is that I am not getting any codes at all. I really don't understand how this can be. The only thing I can think of is that all the oxygen sensors are bad, and the car is thinking everything is ok.
Did you change your cats out? Did you go stock or magnaflow? Thanks.
04-17-09, 07:42 AM
#15
Plugged cats ? I'm having the same issues as you are:
Accelerates slowly then OK until 3K rpm then it bogs sometimes I hear a bang/clunk under the car then it pulls through 3K though not as powerful as before.
Pulled a "too lean code" on both banks a few weeks ago P0171 & P0174.
Cat's stank on Full Throttle for a while but not so much anymore, probably because I'm not pushing FT with the cats being plugged.
Any way I'll be putting some of my tax refund into replacing the cats but I don't know which kind to buy and I can't find that info here on CL. I'm guessing that 2.5" inlet/outlet 13" OAL will work but do I need 2 or 3 element cats, I dunno.
DaveC
Accelerates slowly then OK until 3K rpm then it bogs sometimes I hear a bang/clunk under the car then it pulls through 3K though not as powerful as before.
Pulled a "too lean code" on both banks a few weeks ago P0171 & P0174.
Cat's stank on Full Throttle for a while but not so much anymore, probably because I'm not pushing FT with the cats being plugged.
Any way I'll be putting some of my tax refund into replacing the cats but I don't know which kind to buy and I can't find that info here on CL. I'm guessing that 2.5" inlet/outlet 13" OAL will work but do I need 2 or 3 element cats, I dunno.
DaveC