92 S15 missing - diagnosis?

[92sonomasl]

I have a 92 Sonoma with a 2.5 iron duke/5 spd. manual. Ever since it was new it would stumble when it was cold under acceleration (for the first 1/2 mile or so). The new problem is that this stumbling will occur off & on (slowly getting worse), but I have noticed some patterns. I can always get it it stumble after turning a corner quickly (at any throttle setting), or under hard acceleration most times. I have replaced the O2 sensor, fuel filter, dist cap & rotor (2 x) and plugs (with correct gap). I haven't pulled any codes, but from other threads I'm thinking it may be the coil or associated wiring. As the problem is intermittent, I suspect a ground/electrical issue rather than fuel problem. Anyone out there with similar issues/solutions?

[MT-2500]

Has it got any codes?

[92sonomasl]

Found the problem - had codes for egr valve and coolant temp sending unit. Replaced the egr valve first and it ran fine for 10 minutes or so and then started poppin' and fartin' again. I took the egr off and cleaned it, then installed a new coolant temp sensor and it runs fine now. I suspect that it was the coolant sensor all along, slowly failing until finally it wouldn't run hardly at all. I've replaced the following:

fuel filter
cap/rotor/plugs
plug & coil wires
egr valve
coolant sensor

Thanks for the help!

[MT-2500]

Originally Posted by 92sonomasl

Found the problem - had codes for egr valve and coolant temp sending unit. Replaced the egr valve first and it ran fine for 10 minutes or so and then started poppin' and fartin' again. I took the egr off and cleaned it, then installed a new coolant temp sensor and it runs fine now. I suspect that it was the coolant sensor all along, slowly failing until finally it wouldn't run hardly at all. I've replaced the following:

fuel filter
cap/rotor/plugs
plug & coil wires
egr valve
coolant sensor

Thanks for the help!

You are welcome and.
Thanks for letting us know how it went.

On the EGR valve watch it real close they are bad on getting carbon balls under the plunger.

Good Luck

[Schrade]

Originally Posted by 92sonomasl

I have a 92 Sonoma with a 2.5 iron duke/5 spd. manual.

Good motor / tranny combo. Had it in my '81 CJ-7. Bored, ported shaved head and intake, headers - yup - headers on a 4 holer!!!. Ran like a top. Even put the motor in BY HAND uh huh!