warms up-stalls out

[dansauto]

any ideas, my 94 starts fine (battery fully charged) runs good. then when it warms up (gage half way) it idles up and down, backfires when I step on the gas and stalls out. It will start back up but runs rough. After I let if cool. It does start and idles fine until it warms up again. I though I smelled antifreeze and planned to replace the headgaskets next week (I don't see any stains, milky oil or ****** exhaust-but I am putting the new improved gaskets in anyway) Check engine light NOT on, car has 13K miles, stk manifolds with cats removed and Dynomax mufflers and K&N filter.

 

[Bad_Byte]

I'm not sure if this will be useful or not. You can run the engine diagnosics by:

Cycle the ignition key ON - OFF - ON - OFF - ON do that with in 5 seconds then count the number of times the check engine light flashes on and off. The number represents the trouble code.

There may be more than one number in the code. If so there will be pause between the flashes representing the numbers. Long pauses will represent additional codes.

A display of 55 means the trouble code display is complete.

This is a place to start and its easy and best of all its free.

 

[Ulysses]

How old is the battery. Sometimes that will do it. A battery with a dead cell will sometimes still register fully charged. There were posts of this problem before which also pointed to the engine idle speed motor.

 

[dansauto]

Battery about 2 yrs old, I tried the key thing and it is coming up with a code 12 and 54. 12 is battery disconnected and 54 is cam pos. sensor (that puzzles me because my shop manual states that the check engine light should be on when this code is stored-the check engine light is NOT on?) The battery did go dead on me a cuple of months ago and I have left it on the trickle charger since.

 

[RobHook]

I know this is an old thread but did you ever figure this one out Dan? My '94 just started doing the same thing. I've retorqued the intake manifold and replaced the battery but that hasn't helped. What did you find out with yours?

--Rob

 

[RobHook]

Ok, I think I figured this one out, at least for my car.

Turns out the connection on the MAP sensor was loose. The computer has a code for getting NO signal from the map sensor but it wasn't enough to trip the code. I'd had a similar problem about 6 months ago and found that one of the connection pins on the map sensor had corroded off. I had to drill out the corroded parts of the pin in the wiring harness side of the connection so I could plug it into a new map sensor. Apparently that connection loosened over time producing the rough/no idle and stalling problem but not the trouble code.

Cleaning and tightening the connection to the map sensor seems to have solved the problem for me. I would suggest you disconnect your map sensor and have a look at all the pins and sockets to make sure they're not corroded. My original map sensor was so corroded, one of the pins was completely gone.

--Rob

 

[dandimand]

having a similar problem where is the map sensor located on a 96 gts ?

 

[BOTTLEFED]

driver's side bolted on the intake manifold in front of the wiper motor

 

[dandimand]

Thanks very much

 

[dandimand]

Dont think its that as it seems the wiring is very new there took it off and inspected I think its either the idle air control or its one of the 02 sensors

 

[eucharistos]

wires.....hhmmmm

 

[dansauto]

This was so long ago I cant really remember, but I do know that I had issues with the throttle bodies, esp if you push the thottle all the way. So I had to "re-adjust" them