What a difference cleaning the MAF and air filter makes...
04-01-10, 08:55 PM
#62
I reset the ECU several times already in the past but never got this rough idle. In actuality, it's more of a harsh vibration that steadily goes through the car. My RPM while idle is at 1.5. I put the car in reverse and then engaged my parking brake to check under the hood. The engine does not even vibrate or shake at all. It appears to be running VERY smooth. Mind you no CEL yet to this point. I didn't mention this part earlier but now my focus has now shifted to my front strut bar that I put in that same day 
I'll let it stay as is for a few more days and then remove the stb out to see if this has something to do with it. Mind you while on the highway I was pushing hard at times doing 80-90 to test things out and my fuel gauge appears to not have budged much after the cleaning. For now at least it appears something good may have come out of this cleaning I did.
I hope I don't fall in this category but I've seen little to hardly anyone here mentioning that they screwed up there MAF by using the CRC cleaner.
I'll let it stay as is for a few more days and then remove the stb out to see if this has something to do with it. Mind you while on the highway I was pushing hard at times doing 80-90 to test things out and my fuel gauge appears to not have budged much after the cleaning. For now at least it appears something good may have come out of this cleaning I did.I hope I don't fall in this category but I've seen little to hardly anyone here mentioning that they screwed up there MAF by using the CRC cleaner.
Just a quick story - One time Firestone recommended a Fuel System Treatment, which includes throttle body cleaning, fuel injector cleaning, and a fuel additive to the gas tank. They did a 2004 Honda Accord, which had Electronic Throttle Control. And the car pooped out. The car barely starts. Idles very rough. Need to hold the gas pedal for the car to stay alive. It's because they used the TB cleaner from Wynns. They sprayed the whole throttle body and it soaked the TPS unit and made it become malfunction. So they ended up eatting that by replacing the TPS unit (squared box type) and had to be reprogram the ECU so that it recognizes the new hardware (TPS) so it would function properly.
Just something to think about.
04-01-10, 09:35 PM
#64
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I have been averaging around 17-18mpg on my 03 GS300
do you think doing these cleanings will help alot? i drive highway and city and have always averaged around 16-18mpgs..... which sucks cuz my 06 350Z averaged 21mpg driving the same roads (with even more aggressive driving style in the Z)
do you think doing these cleanings will help alot? i drive highway and city and have always averaged around 16-18mpgs..... which sucks cuz my 06 350Z averaged 21mpg driving the same roads (with even more aggressive driving style in the Z)
04-01-10, 09:38 PM
#65
After putting off cleaning my MAF and air filter, I finally did it a few weeks ago. I've noticed that during my last 3 fill ups, I went from around 310 miles from a full tank previously now to 360 miles off a full tank. That difference of 50 miles is a lot! My daily commute from home to school to work is about 23 miles roundtrip. That means I can go 2 more days before filling up! With gas at ~$4.25 here, I'm glad I had a noticeable improvement. I just thought I'd remind everyone to check their MAF, air filter, and tire pressure if you haven't done so. You'll thank yourself. It'll make a world of difference.
P.S. I drive a 98' GS400 with stock 18" 07' wheels.
P.S. I drive a 98' GS400 with stock 18" 07' wheels.
04-01-10, 09:56 PM
#66
I've heard from several mechanics, including a friend of mine, is to use Chevron's fuel system/injector cleaner. When you fill the tank, pour in the additive and drive until it's empty so that the additive can circulate from the fuel pump all the way to the injectors. I don't think this will "resolve" the problem if there is any since the previous owner had already religiously used regular fuel instead of the recommended 91 octane. It's worth a shot though to see if it may fuel economy. You may try switching out the spark plugs too.
04-01-10, 10:24 PM
#67
Y'all get some pretty ****ty gas mileage! I drive city and highway and get ~100 miles per quarter. I can get well into 400's with only highway. I can't wait to see what I get when I Sea Foam it and clean the MAF and change the plugs. This is on a 99 GS400 with just under 150k and 19in CCW's.
04-02-10, 04:49 PM
#69
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Y'all get some pretty ****ty gas mileage! I drive city and highway and get ~100 miles per quarter. I can get well into 400's with only highway. I can't wait to see what I get when I Sea Foam it and clean the MAF and change the plugs. This is on a 99 GS400 with just under 150k and 19in CCW's.
i have gotten as high as 25mpg on str8 highway, using cruise control.... but if i dont use CC and i accelerate often because of some traffic it drops to 20 on highway...
how hard is it to clean the throttle body? do u need to clean both sides or just intake side???
04-02-10, 10:23 PM
#71
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yep avg 20 mpg on my gs4 (most of ym driving is rural, no stops) highway 22 mpg. in manual mode, through town (just to rip it past teenagers who cant help but stare) i get 14-16
04-04-10, 05:44 PM
#73
Okay fellas so I found out what the issue was only after I came back from being away. The issue had nothing to do with the cleaning of my MAF & TB but was how I installed a front STB recently. The car responded very well and fuel economy was noticeably much better. After I initially used the MAF cleaner, I went back and removed the sensor and used an old shirt and gently wiped some dirt off it. As said many times before here, I recommend cleaning it and resetting the ECU if you haven't done so already.
04-05-10, 07:51 AM
#75
Y'all get some pretty ****ty gas mileage! I drive city and highway and get ~100 miles per quarter. I can get well into 400's with only highway. I can't wait to see what I get when I Sea Foam it and clean the MAF and change the plugs. This is on a 99 GS400 with just under 150k and 19in CCW's.
....they cant help but stare to see whose making all the racket and trying to be cool with what im sure they believe to be your parents car 
hehehe