RLadieu

OK so I'm new here. Here goes my first post! I have been having a weird problem for about 6 weeks now with my 1999 LX470, when I get in my car in the morning she runs perfect for about 3-4 miles then she will hiccup and start running rough with the check engine light on and flashing then about 5 miles later it will snap out of it and run perfect for the rest of the day! The check engine light will stay on solid until she sits all night then it will turn off only to start the whole pattern all over again the next morning. We have changed 2 coil packs (not sure which ones) 2 -O2 sensors on the passenger side, cleaned the fuel injectors and still nothing changes. We have a suspicion that it is something dirty and sticking, only because it clears itself and runs perfect, my husband thinks it has something to do with the choke getting stuck or after the choke goes off for some reason it is getting to much air until it resets itself. When I Google information about the choke nothing comes up, is there another name for the choke on the LX 470? Also everything else seems fine, the temperature gauge is perfect and so are all the other gauges. Does anyone have any idea what this could be? We have already spent $700.00 with our mechanic and he can not find the problem either and if it is just something dirty or sticking my husband can do it for free. Please help, this is getting really old!!!! Thank You

caddyowner

I wish we could welcome you under better circumstances. Have you had your mechanic read the error codes while the check engine light is lit or, even better, during the 5 mile period when the engine is running roughly?

"Choke" is the old carburetor version of restricting airflow into the combustion and forcing the engine to run rich while cold. This is all handled electronically these days to minimize emissions, but his logic that something is causing the electronics for force a rich running condition might not be too far off. Bad O2 sensors can do this, forcing the burning of a rich fuel mixture, and eventually clogging your catalytic converters. I don't know if that comes-and-goes, though. (It happened to my son's S-10 pickup and the performance just got steadily worse until the only way it would get to the Chevy dealer was with open exhaust manifolds. It was within the 80K emissions warranty and fixed for free.)

RLadieu

Thanks caddyowner for your reply. Yes he has read the codes and that's what we have fixed that cost us $700.00 what was coming up on the codes. Now is the EGF Valve the new "choke" because that is something we were thinking could be sticking and has never been cleaned, through research I have found that could be a problem.

Thanks again

RLadieu

Hi, does any one know where the main brain that controls engine functions is located on my 99 Lexus LX470? The part # is 89661-60611 for the ECU that controls the engine functions however we can not locate it on the vehicle so we can change it out. Thanks for any help!!!!!

V8_Fan

IIRC, the ECU is behind the glove box. Make sure your throttle body flap is clean (no sticky carbon buildup). It should be cleaned about every 30K mi. Your problem is not indicative of it (if the TB were the problem, you'd usually get a code that said bad accelerator or TB). At least you could check. I don't see why the ECU would go bad. The other thing is are you using a stock engine air filter, or one of those "performance" lamp shade ones or foam ones that use oil? The latter (uses an oil) gums up the mass air sensor on top of the air box (notorious on the newer 4runners with people running K&N filters). There's a wire in there that gets gummed up with the oil from the air filter. I've seen those disassembled (in Japanese Landcruiser mags) and they use a spray electronics cleaner on the circuitry.

RLadieu

Well we have cleaned every single thing you have recommended, with no results. The code we are getting is an igniter malfunction on # 8, its not the coil pack or the spark plugs because those have all been changed, in fact what sort of lead us to this is when the spark plugs were changed #8 of the old ones was in perfect condition looked like it had never been ignited. And our problem is intermittent as if something is going out. We did find the Engine Control ECU and we are planning on buying a used one, do you know if the numbers on the part have to match exactly as long as it comes out of a 99 LX470? We have noticed there are several numbers being off by maybe 1 for the same exact car and year. And do you know if that year has to be programmed from the dealer, I've heard it's 2000 and newer. Thanks for your help

GS4_Fiend

iTrader: (22)

Engine light flashing = severe misfire. Retrieve the codes and start from there.

kngkong

iTrader: (6)

Oh you are in for a BIG surprise.. I'll explain a little bit more.. let just say, it ******ing cost me 4k+ for fix the problem... I should of drove it off a cliff along time ago..

idsrvit

Hello,
I was wondering if you every got to the bottom of your check engine light issue? My 99 LX 470 started doing the same thing (I am at 191, 200 + some miles on mine). I just recently had the check engine light come on in my car as well. I had the alternator replaced (I dont think the issues were related..just stating it fyi). And while in the mechanic hooked it up to find out what was wrong and nothing was coming up. After replacing the alternator, the mechanic told me the electronics would all have to reset themselves and once I put about 80 miles on it, the light should go out. It took more like 200 miles..but the light did eventually go out for several weeks. About a week ago, out of the blue, it came back on. Now it intermittently comes on and will stay on for several days and then randomly go off. So far...it has been on for about 3 days straight and I am not sure if I need to have it looked at...or ignore it. My fear is I will end up fixing this..that..and the other thing only to end up never fixing the actual issue. Just wondering what you ended up doing..and or if you ever got to the bottom of your issue? Thanks for any info.

RobRed

Buy a $25 code reader and start from the error codes - it's very helpful. Why guess at the systems effected.

idsrvit

@ RobRed... Thanks for the suggestion, in this case it wasnt a matter of guessing... I took my car to Autozone and also to a mechanic...and neither of them were able to get a reading of anything being wrong. After an hour or so of researching the lexus site, I found a few options to look for. The fix ended up being my husband clearing away a bit of corrosion around the battery terminal and the light went out.

***NOTE...light came back on a few weeks later, stayed on for several days..and is currently back to being off. however, still having the same issues with start up and still not showing any codes.

GaryRama

I'm interested to buy a code reader, how much should I expect to spend on a good one and can someone recommend a brand/model?
Thank you.