N/T stutter/stall problem, no codes...

[97GSRyan]

I have a 97 non-turbo, with a worsening stutter problem. I've researched, and the only threads I came across were for turbos. The car normally runs fine, but when it's hot out (around 95+ degrees) it stutters under acceleration. It seems to be more pronounced the harder I press the gas, which tells me fuel delivery? Also it seems worse when the A/C is on.. Only known issue with the car is a "small EVAP control leak" but I'm not sure if that would be related?
So there it is-
1. Stutters worse with wider throttle
2. Stutters worse with A/C on
3. Seems to be caused by heat
4. EVAP control leak possibly related?

Any help/suggestions would be greatly appreciated, thanks.

 

[ibspoolin2]

vacuum leak or maybe get plugs and wires and make sure the gap is right on the plug

 

[smoejoe1980]

my car does kinda the same thing, at idle it will be normal most of the time, but there are times it would drop to about 500 rpm and shake. I turned the throttle idle screw out higher and it still manages to drop to 500 rpm, other times I'll just be driving and it will turn off and i have to turn the key and start it again.

 

[red97tib]

Mine does the same thing, but it is just random and very frequent. I believe it to be a fuel problem as well, I'm thinking FRP. Haven't alot of time to investigate, but I'm pretty sure it's that.

 

[97GSRyan]

vacuum leak or maybe get plugs and wires and make sure the gap is right on the plug

Well, I just got new plugs the other day, I'll have to double-check the gapping.. Not sure if they need to be.. You think the EVAP leak I mentioned would contribute to it? It is a vacuum leak, so I suppose it couldn't hurt to check that, right? Man I hate vacuum leaks...

Thanks for the responses guys, keep 'em coming! I'll probably look into testing the FPR too..

 

[ivatu]

you should check yo o2 sensor

 

[97GSRyan]

you should check yo o2 sensor

That was a thought too, although it's a Bosch that's only about... 6 months old. Hell, the wires are still their true colors, I hope it's still good haha

 

[97GSRyan]

Okay so I checked the spark plugs, and they were gapped wayy too small, about .3mm under.. So i got those gapped and it seems to have helped, hasn't bucked on me yet.. We'll see how it holds up *crosses fingers*

 

[97GSRyan]

Thought I would give everyone a further update and add another question So far, the spark plugs being properly gapped seems to have cured my stutter/stumble issue. Now I wanted to add another question, since I've searched and can't find much on the subject.

I've had a CEL code P0442 for a while now, and just started looking into getting it fixed. I've been doing some vacuum testing which has been inconclusive so far. I recently discovered the "EVAP system test port" so my question is this - Would I be able to connect a boost leak tester to this port to check the evap system? I know there's a leak somewhere and it's not in the vacuum lines. (According to the Autozone tests at least..) If it's of any help I can take a picture of the port too, just let me know

 

[Tim Melton]

Why not put a timing gun on it to see where you are at you might be way reterded.also have the alternator tested.

 

[97gssleeper]

If you have taken the black cover off where the factory smic is at on the turbo vehicles, then I would look at the evap canister behind there. I had a crack there once from a rock or something and caused me to get the code. I put some Goop on it and it's held for 9 years or so now.

 

[red97tib]

If you have taken the black cover off where the factory smic is at on the turbo vehicles, then I would look at the evap canister behind there. I had a crack there once from a rock or something and caused me to get the code. I put some Goop on it and it's held for 9 years or so now.

He has a N/T as do most of us in this thread.

 

[97GSRyan]

He has a N/T as do most of us in this thread.

Correct-a-mundo... Don't even know where the SMIC is on the turbos haha

I'm hoping to check that stupid can tomorrow night though.. As soon as I get more stuff torn out of the way I'll let everyone know what I find.

 

[red97tib]

Just for future reference, the turbo SMIC is on the passenger side behind the bumper.

 

[97GSRyan]

Just for future reference, the turbo SMIC is on the passenger side behind the bumper.

Gotcha.. 97gssleeper, is the "black cover" you're talking about the fender well splash guard?

 

[97GSRyan]

Alright I finally got a chance to check out the EVAP system... All my vac lines seem to be in actually great condition, still nice and soft, no corrosion.. HOWEVER my purge solenoid seems to be operating in reverse.. It holds vacuum with no voltage applied and purges with voltage. Anyone ever heard of this before? The terminal resistance is within spec too which is confusing me. Any help would be greatly appreciated!