95 GT Cold Start Surging, Occasional Stalling, Intermittent CEL

Tolpeko · Feb 6, 2019

Hi all! Sorry to be asking for help in my first post, but I figured it's better than the endless searching I've been doing.

The symptoms in my 95 GT are:

Surges for the first minute in cold weather, usually goes away once I give it some gas and start driving.
Stalling in freezing temps once the car warms up. It wouldn't stay running recently in 20° weather unless I gave it some gas, and putting it in gear was almost a guaranteed stall. It was actually running fine until it reached operating temp.
Intermittent CEL, more frequent the colder the weather. I checked codes but I'm not getting any.

The car runs perfectly other than these issues, but it's not really reliable in freezing weather right now. I went through the checklist of surging issues and thought maybe it's the IAT sensor. The resistance looks good (I only measured one value). The voltage coming out of the connector is 4.5v and I read it's supposed to be 5v. Is that within normal range or is that an issue / what should I test next?

If it helps, here is a service record of what's been done since I got the car. It has no mods other than aftermarket exhaust and deleted EGR.

Thanks for any help/suggestions!!

General karthief · Feb 6, 2019

When you say you get no codes, you should get the 11 for all clear, everyhing checked good.

jozsefsz · Feb 6, 2019

The checklist kind of assumes your car is in a reasonable state of tune. Fresh gas, decent plugs / wires / coils / cap & rotor / fuel & air filters, clean oil, clean injectors, no vacuum leaks (the vapor purge line is always suspect). If your O2 sensors haven't been changed in a long time, a lot of miles, or forever, they're overdue. Cleaning your MAF wouldn't be a bad idea either. I'd start there.

As you mentioned you followed the checklist, your car runs ok with the IAC altogether disconnected? You adjusted the throttle stops and idle air bleed to keep it running (at a low RPM) with the IAC unplugged? You then cleaned the IAC, disconnected the battery for 15 minutes to reset the adaptive learning, reconnected?

If you follow all of those steps, primarily related to the IAC, and your car is in a good state of tune, with all vacuum lines checked, that should eliminate the stalling.

Tolpeko · Feb 6, 2019

General karthief said:
When you say you get no codes, you should get the 11 for all clear, everyhing checked good.

Yep, my mistake, I meant all clear, at least for KOEO. I do get 311 and 314 (AIR system inoperative) during KOER, but I thought that was from the EGR delete.

jozsefsz said:
The checklist kind of assumes your car is in a reasonable state of tune. Fresh gas, decent plugs / wires / coils / cap & rotor / fuel & air filters, clean oil, clean injectors, no vacuum leaks (the vapor purge line is always suspect). If your O2 sensors haven't been changed in a long time, a lot of miles, or forever, they're overdue. Cleaning your MAF wouldn't be a bad idea either. I'd start there.

As you mentioned you followed the checklist, your car runs ok with the IAC altogether disconnected? You adjusted the throttle stops and idle air bleed to keep it running (at a low RPM) with the IAC unplugged? You then cleaned the IAC, disconnected the battery for 15 minutes to reset the adaptive learning, reconnected?

If you follow all of those steps, primarily related to the IAC, and your car is in a good state of tune, with all vacuum lines checked, that should eliminate the stalling.

Yep it is in pretty good tune and has basically a new/clean everything. It was running horribly before that, but there's still this one little issue remaining. I haven't checked it with the IAC disconnected so I will look into that. I can't rule out a vacuum leak either!

Thanks for the replies!

95 GT Cold Start Surging, Occasional Stalling, Intermittent CEL

Tolpeko

New Member

General karthief

wonder how much it would cost to ship you a pair

jozsefsz

Tolpeko

New Member

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95 GT Cold Start Surging, Occasional Stalling, Intermittent CEL

Tolpeko

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General karthief

wonder how much it would cost to ship you a pair

jozsefsz

Tolpeko

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