[304steeley]

88s10 has been shaking and will surge or just stall out soon as I shove the clutch in and while slowing down . Problem started a few months ago. It’s steadily got worse since the issues started . Seems to do it worse when it’s colder outside and it just recently started stalling out every time I shove the clutch in when slowing down . It initially would fire right back up . Lately it has been hit a miss a will fire up then die . Will do it when just idling now sometimes also . I have cleaned the throttle body , and cleaned and changed pcv valve , IAC sensor, spark plugs, wires, distributor cap and rotor button, air filter, egr valve , MAP sensor , checked for all vacuum leaks, it acts like it’s starving for fuel when slowing down. Any advice would be greatly appreciated, . Runs perfectly fine when at highways speeds .

 

[aitch]

Sounds like a well fed parts cannon, but without positive results.

 

[304steeley]

If I knew how to diagnose the problem I wouldn’t be on here asking for advice .

 

[PeteD]

If I knew how to diagnose the problem I wouldn’t be on here asking for advice .

If you know someone with a quality OBD1 SCANNER, this would be good time to look at running data stream. If it will static idle, try 'wiggle' test on all wiring, vac hoses. Stated possible symptom of fuel starvation when decel smacks of vac leak . Could EGR be sticking?
@ 34 yrs of use , it's subject to unusual aging issues

 

[S15E83]

Sounds like a classic vacuum leak. How did you check for them?


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[304steeley]

If you know someone with a quality OBD1 SCANNER, this would be good time to look at running data stream. If it will static idle, try 'wiggle' test on all wiring, vac hoses. Stated possible symptom of fuel starvation when decel smacks of vac leak . Could EGR be sticking?
@ 34 yrs of use , it's subject to unusual aging issues

I will have to stop at my buddies and try . I plugged the egr valves vacuum hose off and just did away with it . There wasn’t any suction from the line . The issue started awhile before I did that . I was wondering if maybe it had something to do with my transmission?

 

[304steeley]

Sounds like a classic vacuum leak. How did you check for them?


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With the motor running took brake cleaner a sprayed real good all over all the lines and anywhere there could possibly be a vacuum leak . It stayed at a steady idle

 

[msdibble]

The OBDI "scanner" consists of shorting the two right pins on the OBD connector with a paper clip..LOL. You have to read the "Service Engine" flashes to tell what the problem is. Google "S10 OBDI codes".
I had all sorts of problems with my 88 S10 2.5L and finally was able to diagnose as a "Computer" via the OBDI flashes. Those computers can be hard to come by. You have to have the exact same Serial Number..If you are looking in a junk yard or maybe on-line somewhere. Your truck's computer is a book-sized metal box - accessible under by a small attaching screw and located under the dash, behind the glove compartment. It's kind of a bear to wrestle out, but you can get it.
The Serial Number is: EM7165S.
Once you find the computer body, you will have to remove the cover plate (Two Machine Screws) and pop out the EPROM (a clip on either side). Replace it with the original EPROM from your truck's computer. Then plug it back up and you're in business!
I did that and now my 88 S10 2.5 runs like a champ!!
Good luck!

 

[PeteD]

I will have to stop at my buddies and try . I plugged the egr valves vacuum hose off and just did away with it . There wasn’t any suction from the line . The issue started awhile before I did that . I was wondering if maybe it had something to do with my transmission?

If it's 'smoked' or torque converter's broken

The OBDI "scanner" consists of shorting the two right pins on the OBD connector with a paper clip..LOL. You have to read the "Service Engine" flashes to tell what the problem is. Google "S10 OBDI codes".
I had all sorts of problems with my 88 S10 2.5L and finally was able to diagnose as a "Computer" via the OBDI flashes. Those computers can be hard to come by. You have to have the exact same Serial Number..If you are looking in a junk yard or maybe on-line somewhere. Your truck's computer is a book-sized metal box - accessible under by a small attaching screw and located under the dash, behind the glove compartment. It's kind of a bear to wrestle out, but you can get it.
The Serial Number is: EM7165S.
Once you find the computer body, you will have to remove the cover plate (Two Machine Screws) and pop out the EPROM (a clip on either side). Replace it with the original EPROM from your truck's computer. Then plug it back up and you're in business!
I did that and now my 88 S10 2.5 runs like a champ!!
Good luck!

Excellent description of an excellent work around for ancient electronics

 

[304steeley]

The OBDI "scanner" consists of shorting the two right pins on the OBD connector with a paper clip..LOL. You have to read the "Service Engine" flashes to tell what the problem is. Google "S10 OBDI codes".
I had all sorts of problems with my 88 S10 2.5L and finally was able to diagnose as a "Computer" via the OBDI flashes. Those computers can be hard to come by. You have to have the exact same Serial Number..If you are looking in a junk yard or maybe on-line somewhere. Your truck's computer is a book-sized metal box - accessible under by a small attaching screw and located under the dash, behind the glove compartment. It's kind of a bear to wrestle out, but you can get it.
The Serial Number is: EM7165S.
Once you find the computer body, you will have to remove the cover plate (Two Machine Screws) and pop out the EPROM (a clip on either side). Replace it with the original EPROM from your truck's computer. Then plug it back up and you're in business!
I did that and now my 88 S10 2.5 runs like a champ!!
Good luck!

What would make you certain that the computer is what is causing the problem ? Just wondering because I’m tryin to save myself from replacing any other unnecessary parts

 

[1stiski]

Just reading this I remember when my 88 , 2.5 with the 5 speed was doing the same thing , except the truck had less than 10,000 miles on the odo. (Now over 190,000) but , my truck would do weird stuff , exactly as you explained , it ended up being my chassis ground to the computer when all the chasing ended .

 

[aitch]

What would make you certain that the computer is what is causing the problem ? Just wondering because I’m tryin to save myself from replacing any other unnecessary parts

The #8 post sounds like a description of what was experienced and done for that particular vehicle/ incident, rather than a 'this is what's wrong' statement regarding your vehicle. You posted you are seeking advice, and this appears to be an offer of a possible reason for your problem. Checking for codes can at least help guide the search for the problem. If, after checking the computer and any codes presented, and if all checks out OK, then that could be likely ruled out as an "unnecessary part" to replace.

 

[PeteD]

88s10 has been shaking and will surge or just stall out soon as I shove the clutch in and am slowing down . Problem started a few months ago. It’s steadily got worse since the problem started . Seems to do it worse when it’s colder outside and it just recently started stalling out every time I shove the clutch in when slowing down . It initially would fire right back up . Lately it has been hit a miss a will fire up then die . Will do it when just idling now sometimes also . I have cleaned the throttle body , and cleaned and changed pcv valve , IAC sensor, spark plugs, wires, distributor cap and rotor button, air filter, egr valve , MAP sensor , checked for all vacuum leaks, it acts like it’s starving for fuel when slowing down. Any advice would be greatly appreciated, . Runs perfectly fine when at highways speeds .

Most electrical problems are 'ground' related. Good start on most older/rusty vehicle's is Reestablish All Grounds with sandpaper, nu star washers, etc as needed in problem related circuits

 

[304steeley]

Finally found the issue with it being the computer. Thanks everyone for the advice

 

[msdibble]

What would make you certain that the computer is what is causing the problem ? Just wondering because I’m tryin to save myself from replacing any other unnecessary parts

The "Service Engine Soon" light will flash a specific number of times and tell you that the computer is the problem. That's what happened to me and my '88.