meemomiller

I have a 1988 chevy 1500 with a 305, a couple weeks ago it got to running rough and then completely stopped when you put it in gear. We have replaced egr valve, plug wires, distributor, ignition controler, spark controller, fuel pump, fuel filter, water temp sensor, computer, injectors, rotorary on distributor, etc. After replacing ignition controller the truck began to run better but when you try to drive it, it has no power. We checked timing, spot on. No vacum leaks. Not sure what to do next. Any ideas? Strangely for whatever reason it runs better when the water temp sensor is unplugged, runs much smoother.

Nomad65

Double check your EGR I bought a new one for my 88, 1500 and the thing was bad from straight out of the box.
Also make sure your fuse's and your computer is ok, sounds stupid but its happened before.
And here's one did you get some bad gas?
Good luck

meemomiller

Gas is good and so is EGR, but talked to a auto mechanics teacher who races dirt track and he said to him it sounds like the diaphragm in the fuel pressure regulator had worn out. Going to do a throttle body rebuild on it, diaphragm was pretty well worn out. Definitely going to have to do a major cleaning of the throttle body though, it pretty corroded. New computer didn't help either.
Thanks for the advice, by the time I get done were going to have a new truck. LOL

Kiss4aFrog

If unplugging the temperature sensor makes it run smoother it's because the computer would go richer with the loss of that sensors information.

That would tend to make me think you might have a vacuum leak or not enough fuel. If the regulator is bad and not holding enough pressure that could well be.

Do you have a check engine light ?? Have you tried to pull codes anyway ??


For that matter, is it fixed already and if so what did you find

JimW

Well you have already thrown just about every part in the store at your problem but I don't see where you checked for any trouble codes ? Before you can prorperly fix something, you need to know what is the problem. the OBD-1 system could tell you a lot about your exact problem , but since you have changed so many parts, I'm not sure it will be of any use now. but I'd drive the truck for a hundred miles and see if the "Service Engine Soon" light comes on.

Kiss4aFrog

I forgot to mention that if the EGR was hanging open that would be a vacuum leak and cause the engine to be running lean and rough.