beerMAN

I own a 94 pickup v6 3.0l and it runs great. I have a problem that has been increasingly happening more often. When the engine is warm, about 30mins of city driving and after letting it sit for about 10 while in a store it has a really rough idle start (300-500rpms). If you do not rev the engine it will die. It almost seems as if it miss fires, but i replaced my spark plugs/wires, dist cap/rotor, re-gen'd k&n air filter. I took it to my friends shop and had them take a look at it, but of course the problem never happened, but they said it might be an ERG? haha whatever that is. But when the problem arises and i am able to drive it, after about 5 mins in a crusing gear (3rd -5th) it's seems to be fine. But when the engine is cold, works like a charm and shows no loss of power or anything.

8422r4Runner

Have your cold water temp sensor tested. It tells the computer the temp of the water. When it is cold, the computer knows to richen up the mixture, as the sensor senses the temp raise it tells the computer, so it leans out the mix.

I think your sensor is failing, so the computer is never told to lean out the mix. So it acts like a car with a carb when it's flooded. When you do get it to start it runs real rich, makes it act like it's missing, cause the fuel/air mix is not right for a warm motor. it still getting as much gas as it would if it was cold. Has your gas milage dropped lately? If yes, that could point to the rig running too rich all the time. it would also explain why it runs so good cold.

Of course it could be a few other things, but that's my guess.

YotaJunky

The apparently infamous warm-restart stumbling. I've been experiencing that for the past 6 months. If you find a solution let me know. I changed out my O2 sensor and it helped a little.

Troy

mtrdrms

I have been having the exact same problem! Except mine doesnt actually die but it will run very rough and stay around 250 rpms. But when I start driving it is fine until I come to the next traffic light. I am gonna raplace the water temp sensor because this is the second time I have been told that this is most likely the problem. Thanks guys and Ill let you know how it goes.

beerMAN

Thanks... i'll try the water tester out, cuz it makes some sense... also im going to replace the fuel filter and only use chevron gas.. i heard that Arco, Safeway, Am/PM gas really sucks balls.

motoracer47

theres no need to replace the sensor without knowing for sure. you can probe the sensor terminals with a volt meter, and compare the resistance with that in the factory manual, then you know if its the temp sensor or not. beerman, once the vehicle is up to temp, do you have any problems? or only when its up to temp, been parked for a bit, then on restart? i may be wrong here, but if the water temp sensor was out,and the ecu thought the engine was cold all the time, wouldnt it overfuel all the time?

also, when you first start the truck in the morning(or whenever the engine is cold)do you have any problem starting the engine? any hesitation like for a second it does not have fuel, then it starts up?

raceguy218

I have a similar problem except mine shuts down while driving and will not restart. Here is the list of new parts installed. Dist cap, rotor, plugs, fuel filter, fuel pump, O2 sensor (which had a CEL for), engine coolant temperature sensor. Still the same. I have not changed coolant temp sendor for gauge because it works correctly. Could that still be it ? Any other ideas ?

Desperate now. Help.

beerMAN

I was talking to my buddy, and he thinks mine is with my o2 sensor, says that toyota's are kinda known for running hot, but im going to find a store that will test it for me and see if that is wrong. It's kinda a pricey part from what i remember looking into ... but it's a nice sunny day i'll replace my fuel filter today.

motoracer47

im going to check to make sure, but i thought with toyota obd1 systems, that on initial engine start, even if the engine is warm, its still in open loop mode for a certain time fame. if thats the case, then the o2 sensor would have no part in fuelling at that time. let me make sure on that, but i could have swore i read that somewhere, i think in the engine systems book. ill grab it and read it tonight.

regularguy412

Please do. That would be good info to know.

Mike in AR

impalla350

My 87' 22re was doing the same thing, i was told it was the Water Temp Sensor, so i unplugged it and it is running perfect.

abecedarian

try something-
turn the key on without starting the engine, then off, then on and off again as mentioned two more times and see if the problem persists.