I have a 1987 305tpi w/t-5 Iroc that has been giving me problems since I bought it last may. It used to only occur during or after wet weather but has recently been running poorly more often. When the car is running poorly, it has a bad hesitation, anything more than 1/4 throttle causes it. Prior to the winter the problem was only present during or after rain. Sometime in december I took it to the car wash one last time to put the on cover I just bought. I shut it off to go into a store, when I came back out it would barely crank over followed by some backfiring. When I finally got it started it was with the gas to the floor. I had to keep it around 2500 rpm to keep it from stalling as really slip the clutch to get it home as it had almost no power. At this point I just wrote it off as a wet weather day and the water from the car wash making it worse. About a month ago it backed it out of its spot to shovel all the snow out and let it run. I then turned it off and it wouldn't start again. It didn't want to turn over easily. I pushed it back in the space and left it. This was on a dry day. Earlier this week I replaced the coolant temp sensor thinking that may have been the cause. The old sensor was completely missing the plastic part that allows the connector to clip on. When I saw this I was sure this was gonna fix it. I put the new one in and it started right up, once warm I shut it off and started it again, no problems. I took it around the parking lot and it ran the best it has since owning it. Shut it off again and started it again, no problem still. Went inside and ate dinner, came out and would barely crank over. I had to start it with the pedal to the floor and once running it had that really bad hesitation. This also was on a dry day. Today I went back out to check fuel pressure and it started right up, ran good however I did not drive it around cause of the snow. Fuel pressure seemed normal, around 42 at idle, 45-48 with throttle. I am going to check the fuel pressure again when it begins acting up to see if there is a difference. Any ideas what to try next? I was fine with it running bad in rainy weather but now it seems to be completely random and I can't trust driving it anywhere. Thanks in advance for any help.

 

Find out your fuel pressure when it is acting up. Maybe the fuel pump is getting hot and not working properly. Coils and ICM's can have issues with heat as well but your issue sounds more like fuel because you can keep it alive with the throttle.

 

Took it out tonight, ran horrible on the way out. Parked for 5 hours. Ran great on the way home. When it's running bad it stumbles under load. If I gradually accelerate it goes but if you give it more than 1/4 throttle it shakes and stumbles. The higher the rpm the better it drives, low end is where it is worst. Stalls out when the clutch is in and hard to restart. Cranks over slowly. When not acting up it drives fine. Starts fine. Doesn't stall. Fuel pressure looked maybe 1-2 psi lower but really close to the same. It seems strange that it would randomly run so well after running so bad and I'm trying to avoid doing the fuel pump if it might be something else.

 

Just read the codes and the only one was code 15: coolent temperature Sensor low temp

I replaced the sensor last week and it didn't change anything. Could it be shorting out somewhere?

I've read other people's posts with similar issues and some are saying injectors and others fuel pump. I think my pump is ok. Today was around 39 at idle, 45 when cracking the throttle and the engine still stumbles at the same time. Any ideas?? It's deffinetly related to engine temp. Runs great for about 5-7 minutes then steadily declines once warm.