1990 Chevrolet K2500 350 5.7 TBI / Runs rough after installation of new fuel injectors and throttle body rebuild kit

Asked by Jan 10, 2016 at 12:24 AM about the 1990 Chevrolet C/K 2500 Scottsdale Extended Cab SB 4WD

Question type: Maintenance & Repair

I have done a rebuild kit on my throttle body.  Tore down to nothing. cleaned
everything up with throttle body cleaner. Replaced the fuel pressure
diaphragm, new fuel injectors, along with gaskets. Put back together and
installed on manifold. Hooked everything back up. Before a full start up, half
cranked over to build fuel pressure back up. Go to do a full start up and truck
starts, then which dies seconds later. While it runs in those seconds it
fluctuates rpms and runs rough. Truck stays running while foot on the throttle,
but note still runs rough. Fuel does come out the injectors while running.
doesn't smell flooded. All replaced gaskets do not leak nor does the
diaphragm. Could it be possible i have to re-time the time that now its getting
the correct fuel pressure? What do i look into here i am lost?

New fuel pump, lines tps and iac

3 Answers


not enough info///is it fuel or elect/vac at this point??


Sounds like there is a vacuum leak. Spray carb or throttle body cleaner around areas where work was done if vehicle starts to run right vacuum leak is in that area.


Are you 100% sure you put the plug wires on in the right order? 18463572 is the firing order. Any time you remove the distributor you need to time it. And as stated check for vacuum leaks. Also try the paper clip method to pull codes. It might help see something and give an area to focus on.

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