'92 SC400...only runs good when it's cold..need help!!!
 

My sc400...tends to only run good and work properly when it's cold..my guess is that it needs some electrical repairing but i'm not sure. I driven for a long time the car tends to start jerking...it also won't go over 70 so i need to figure out wats wrong..any suggestions???

Can't go over 70? Only thing I can really think of is maybe resetting the ECU.

Anyone else care to chime in?

It sounds like a TPS (Throttle Position Sensor) problem and the car is going into limp home mode.

Sounds like the IACV

replacing my ecu helped that out. It felt sluggish when warmed up, but felt very fast and sporty when the engine was cold and heating up.

On those cold mornings does white smoke pour out of your exhaust? Does it smell like fuel? If it is, then I recommend swapping out ecu's to see if it helps out.

But this wouldn't explain why your car cant go past 70?

I can smell fuel on real cold mornings, like 30 and below, when I first crank mine up, but dissispates after about a minute. Does this mean my ECU is bad, or going bad? Know you all have me curious. I dont smell it when its parked in my garage on cold mornings, just when its been sitting outside the whole night.

If you see a lot of white smoke pouring out then your ecu could be bad. But if not then it sounds normal.

It's supposed to do that. Cars run rich on cold starts to heat up faster. You probably don't notice it as much when you park inside because it warms up faster.

If it's idling high I would agree, but that would'nt have any effect under acceleration. She might want to have basics checked like the fuel filter, air filter, PCV or maybe even checked for a vacuum leak.

I have heard some good guesses, nothing spacific you have stated would lead you to any logical easy repair. Too many things could cause problems like those. I would recomend having the dealer check your car for the drivibility problem you are having. If you were in denver I could look at it for you, without a technition who knows can understand/interpret the info to fix your problem, you would have the same "good help" from a auto zone free code check and diag. Worth the 100$, just my .02 GL.
-on that note do you have a ck eng light on? Is it flashing? Do you smell gas even when the car is warmed up? Feel free to pm me if you can not find any better answers.

Maybe get one of these? - San Tool

Cheaper here

I have one, but I also have several OBDII cars. Don't know if it would be worth it to you or not. I have had it see codes when the CEL is not on.

i have the same prob and havent had any help..but i will tell u what i have tried

i have tried the

12v mod--no help

cleanin the iacv--not much help

cleaned injectors --a tad bit

also took off the intake and fully cleaned the intake helped at first but went back to bein slugish

did the fuel tune up wires plugs and cap and rotor --seem to help a little

also relocated the driver harness--still the same

im in the process of still goin thru alot more clean up to see what the prob is

Is your check engine light on? If not run for codes anyways. Sometimes the check engine light doesn't come on but still throws a code. I would start there.

thanks love..i will be sure to check that out!!!

thanks 2 everyone!!
 

all of ur inputs has helped me alot...i've been told numerous times that it can be the sensors...i will hit up an autozone manana for the diagnostic test, since its free..then let u guys kno the latest..again much thanks bcuz i was in the brink of given up on my baby...i really wanna fix her up..juz need to kno where to start