Stalling at low RPM only under load.

I have a 1993 305 Caprice, it likes to act like it's stalling when accelerating at low speeds. It doesn't do it all the time, but it does it A LOT. I've replaced the TPS and the Fuel Filter so far. I'm thinking it's a weak fuel pump, because... I don't know, but that's what I think it is.

It runs rough occasionally at highway speeds, but that's usually when I have no problems. I was going to check the fuel pressure but the store I went to didn't have fuel guages redily available and they would have been $100+++, plus I'd need the right fittings and such.

When I press the gas it starts chugging and theres a LARGE loss of power, if I press the gas very quickly and repeatedly I can get it to rev high and let it sit at higher RPMs for a few seconds and then usually the problem goes away.

Any suggestions? Sound like a weak fuel pump, or something else?

Thanks for reading all this! :biggrin:

This sounds like a common problem for the 305's. Mine had the same exact problem that you just described to every detail. I also changed the fuel filter but that wasn't the problem. I am almost 100% sure that it is your plugs and wires. Thats what i changed and it runs so much better give that a try it is a pretty cheap fix and it should work. If it doesn't i would be totally stumped and its hard to stump a mechanic...

Sounds like EGR valve. Plug the vacuum line at the EGR to see if the stumble goes away. They don't last forever and they take a lot of abuse with exhaust heat.

//2000CAYukon

EGR valve makes alotta sense.... our '89 gmc van did it, and it was the EGR valve. Fixed it right up. But don't eliminate the possibility of the plugs and wires.... also check for any engine codes if you haven't done it already.

It was the Fuel Pump, I changed it out friday, thanks for the replies guys. I can't wait to buy a Caprice Wagon... It'll be nice to have a car with <222k miles...