96 SL with bad accelerator pump???

Just wanted to suggest that the stumble on acceleration could very well also a sign of running too rich (and not necessarily too lean). This appears to be the first message posted in this thread from my news server so I have no idea what other symptoms or actions you have taken.

How exactly has the mechanic "checked" the items you have listed? Is that mechanic competent and familiar with Saturns? Are the plugs and wires new and are they gapped correctly? Have the fuel and air filters been replaced? Are there any obvious vacuum hose or manifold leaks? Is the EGR valve functioning properly? Have you looked for and cleaned off corrosion on the coil towers? Are the engine and body ground wire connections all clean and tight? Are all the injector connectors clean and tight? When was the last time the throttle body and AIS were properly serviced? Have you removed the plugs and were they carbon fouled or oily?

Good luck. Post what you find?

Bob

Thanks for the quick response Bob. Plugs are new and gapped, EGR valve is working, air filter has been replaced in the last 5000 miles, plugs are clean, engine ground wires are good and tight, and the throttle position sensor has been replaced. Im not sure what you mean by "throttle body and AIS were properly serviced". My mechanic, and his other two men have had at least 20 years experience on almost every brand of car including a hundred or more Saturns. This morning he has found that the fuel pressure is 35 psi, and should be, by the book, 45 psi minimum. He is going to replace it, and I hope that was the problem.

Thanks. Here's to hoping it is the fuel filter and this solves your problem, assuming that is the "it" that is being replaced. If not, the fuel pump will be a bit more expensive.

Bob

Which plug gap spec are you using? In '96 the spec was changed to .60", but then was changed back to .40".

The throttle body plates are notorious for accumulating carbon and benefit from a good cleaning with TB cleaner and a nylon bristle brush.

Ken

This saga is getting a little long, so I am going to top post this so those knowing the tail won't have to page through all of the details. My mechanic has replaced the fuel filter, no solution, fuel pump, no solution, and then fuel air ratio sensor, but still no solution. I am going on a trip of about 1400 miles starting tomorrow, and when I get back will see if the Saturn dealer can diagnose the problem. I really want to find the exact cause, Im an engineer if you could not guess, and not just replace parts until it works.