Me and my grandpa recently bought a 1987 chevy R-10 for my first vehicle, when we got it, it had a huge hesitation when you accelerated and if you gave it to much gas it would kill. We change the distributor cap, rotor, plugs, plug wires, and rebuilt the tbi. The hesitation was a little less, so my grandfather took a coil off of another one of our old trucks which is a 1992 chevy 1500. The hesitation went away a little more but is still there. Me and my grandpa could really use some information to get this hesitation out of this thing. Thank you.

 

Probably the fuel pump going south or a bad FP regulator. Did you check the fuel pressure? Did you install new or rebuilt fuel injectors when you did the TBI overhaul?

 

We will check fuel pressure and no we did not change the injectors just cleaned them up. But when you have it in park it revs fine and there is no hesitation but when you put it in gear and actually drive it around it hesitates, Could it still be with fuel pressure then?

 

It could be the fuel pressure regulator, or the fuel pump isn't putting out enough pressure. In my experience, most electrical auto fuel pumps simply fail real quick, but not always. You didnt mention changing the fuel filter, so that might help.

I would certainly change the fuel injectors on an old TBI pickup like yours. You can buy rebuilt ones for as little as $30 dollars per injector (and you only need two) with a core charge, or its about $95 dollars per unit for new ones, with no core charge.

You can try soaking them in naphtha type solvent, but its not likely to work as they are old and the o-rings and other parts are likely hardened.

 

It has a new fuel filter and good fuel pressure. Should i do the 9 volt battery trick on the injectors to see if one doesnt work?

 

No need for that. You can look down the TBI unit and see if the injectors
are working properly. What was your fuel pressure anyhow ?