91 s10 hesitation and jerking

hi all i have a 91 s10 4.3 tbi 5 speed, for about 3 or 4 months its
been hard to start cold or hot. turns fine just take a few to start
once started and on the road it hesitates like at a stand still have to floor pedal for a few then it kicks in does this though all gears until warm
then it runs like a dream. could drive all day but shut down for a few
thenall problems happen again. on engine lightsever came on so no codes stored , changed map , eac solenoid, egr good, thottle body
cleaned and all gaskets changed, plugs, wires, cap rotor, fuel filter,
does anyone have any other ideas???? i would appretiate it.

Check your vacuum with a guage and check for vacuum leaks.

thanks ill do that kind of expect that because seems to be a wet oil spot around intake thanks ill get back with you soon

took a stethicope and listened for hissing but nothing
could a going bad coil pack do this?

If you have access to a scanner that will allow you to view data, check to see the output of the TPS (Throttle Position Sensor).

If you want to shotgun and change it, that is also your choice.

hi all i have a 91 s10 4.3 tbi 5 speed, for about 3 or 4 months its
been hard to start cold or hot. turns fine just take a few to start
once started and on the road it hesitates like at a stand still have to floor pedal for a few then it kicks in does this though all gears until warm
then it runs like a dream. could drive all day but shut down for a few
thenall problems happen again. on engine lightsever came on so no codes stored , changed map , eac solenoid, egr good, thottle body
cleaned and all gaskets changed, plugs, wires, cap rotor, fuel filter,
does anyone have any other ideas???? i would appretiate it.

Checked the timing lately?

yes done on last tune up 2 weeks ago

Did you disconnect the timing wire from the ECM when you were setting the timing?

yes it was under dash set straight up 0 tightened
distribitorand hooked connacter back

sounds like the fuel pump strainer is clogged or the pump is not priming properly OR the fuel pump check valve is leaking allowing the fuel to leak out of the system and losing your prime.

When you start it up, do you go to the on position so the fuel pump can prime and then start it.

thanks ill check it out i really do appretiate all the help
again thanks

I cant remember does that have a tbi or spider inj under the plenum(intake)
Fireplug.
The spider inj are known to leak and cause the problems you talk about

all i know is i have a tbi system. i dropped the gastank
took out the pump tank and pump screen were clean.
all hoses and lines good shape. put it all back together and test drove it after letting it warm upand idle was smoothened out. drove great. still alittle hesitation at first but much better. ill let you know how it performs this afternoon. thanks.

CPI stated in 1992 and the 1991 only had the TBI I believe.

Check the timing again just to be sure it was set properly.

hi all i have a 91 s10 4.3 tbi 5 speed, for about 3 or 4 months its
been hard to start cold or hot. turns fine just take a few to start
once started and on the road it hesitates like at a stand still have to floor pedal for a few then it kicks in does this though all gears until warm
then it runs like a dream. could drive all day but shut down for a few
thenall problems happen again. on engine lightsever came on so no codes stored , changed map , eac solenoid, egr good, thottle body
cleaned and all gaskets changed, plugs, wires, cap rotor, fuel filter,
does anyone have any other ideas???? i would appretiate it.

Is there any resolve to this type of problem, I have basically the same problem as above, except my S10 is a 2.8L V6, 1988, TBI, with 5 Speed Manual. I have tried all of the above repairs to no avail. I have hesitation, backfires and engine stopping until it gets warm, any acceleration makes it worse. When dirven 10 miniutes or more, it is fine. The only codes I get are 12 and 24.

Check the gasket under the tbi unit they go bad and suck air when hot.
That was a common problem.
Take a can of carb cleaner and spray arround the base of the TBI unit and check for any rpm changes.
If it goes up it leaking
Be carefull not to do it full blast on the spray or it will get sucked into the tbi and cause a fake rpm change. Or use wd-40 also works
Fireplug

what gasket is the one in between the tbi and the intake

replased it when i bought the thottlebody gasket kit
replaced all gaskets and seals replaced regulator too
im at wits end. ill check timing again. thanks.

If you can get a scanner hooked up to it check the coolant temp sensor with the engine cold and see what it reads
Fireplug