1999 Sunfire Runs Bad When Raining Or Humid

[gorillago]

I have a 1997 Pontiac Sunfire 2.2L that has been giving me this issue for a LONG time now. It's been getting a lot worse recently, so I thought I'd put some more effort into fixing it. Occasionally when It's raining or really humid outside, my car will spit and sputter, and not idle. Some days it's bad enough to where you can be driving it. Press the clutch, and the engine will just stop running while you're rolling down the highway.

I've tried replacing plugs and wires on it before, the coil pack is fairly new so I don't think it's the problem, though I wouldn't completely rule it out. I just recently replaced my rear O2 sensor, which got rid of the engine code I had, so I thought it was fixed, but the issue continued happening. It seems this issue causes misfires and the car will barely run, but it doesn't throw any codes?! Any ideas would be appreciated. I was thinking it seemed like possibly the IAC, but I don't think that'd have much to do with moisture. I saw some places it could be throttle position sensor, but I seriously doubt that's it.

Any input would be appreciated!

 

[Zimgxp]

Moisture getting onto a plug somewhere?

 

[melsg5]

as Zimgxp mentioned you have a corroded electrical connection somewhere and moisture causes it to fail. You could try washing small sections of the engine with a hose to try to narrow down where the problem is.

 

[gorillago]

Is there anywhere specifically that you can think of that would be that sensitive to moisture? This happens even on humid days when it's not raining. I'm at work for 3 and a half more hours, but when I left for my lunch break, I have to fight to keep it alive when I let off the gas. It didn't used to happen as often, I've had the car nearly 2 years, and recently it seems it happens consistently when it's humid, or rains. Also one time I drove through a puddle and the engine seemed to be missing almost every other fire. Like I went through this puddle and there was a big splash, and if I got into the gas at all, it would just spit and sputter. I hope some of that info can help narrow down some things?

______________________________

 

[melsg5]

it could be almost anything related to electrical, describing it doesnt narrow it down. You have to perform at least the basic test of wetting down the engine in small sections to see which connection is causing your problem.

 

[gorillago]

Right, I'm still at work, but I'll let you know what I find out when I get a chance to mess with it. Thanks!

 

[gorillago]

Coil Packs

I replaced my coil packs, because I highly suspected them. It seems to have solved most of the problem, but the car still isn't running quite right, still stutters when you lay into it to take off. I think it may have something to do with the intake system.