Questions and Answers

Chevy Cavalier Bogs Down, Runs Rich Q. Dear Vince, I am at my wits end. Have been to the mechanic. I have replaced TPS, OS, IAC, EGR, CTS and ECT. The only thing not replaced is the MAP sensor and air intake sensor. This vehicle does not have a TSS or MAF. Tuned up, new ignition module, wires and plugs. Vacuum holds 19 to 20", slight fluctuation of 1" between these numbers. Indicating secondary ignition problem?

Anyway for the most part the car does beautifully, but occasionally takes a notion to act-up, usually at highway speed when slight acceleration is applied. It bogs down into a super rich mode, black out the tailpipe and no power, bucks like hell too. Starts making this weird sound. It will have occasionally a wild fluctuating idle until stall, but a tap of the gas corrects this and it idles fine. The throttle plate is normal close, no modification.

At highway speeds when accelerator is eased off, this stumbling and surging happens too. It has been a good car and I've seen it run greta with great mileage lately, but this? 1990 Cavalier CL (TBI - model 700) 2.2 liter engine, automatic transmission and A/C.

Anyway for the most part the car does beautifully, but occasionally takes a notion to act-up, usually at highway speed when slight acceleration is applied. It bogs down into a super rich mode, black out the tailpipe and no power, bucks like hell too. Starts making this weird sound. It will have occasionally a wild fluctuating idle until stall, but a tap of the gas corrects this and it idles fine. The throttle plate is normal close, no modification.

At highway speeds when accelerator is eased off, this stumbling and surging happens too. It has been a good car and I've seen it run great with great mileage lately, but this? 1990 Chevy Cavalier CL (TBI - model 700) 2.2 liter engine, automatic transmission and A/C.

This is supposed to be the VL, value leader, but no, it's a 1990.5, sort of unique, first 1990 with the G engine OHV. Production date: 12-89. The insurance company gives me a discount for passive restraint system this car does not have. Appreciate any help. I've spent enough, but the car is really clean and uses or leaks no oil. It has 208,700 miles now.

A. Have you had a fuel pressure guage put on it? It could be a bad PCM or ground wire to it. Are all the parts you repalced GM? Some aftermarket parts are junk! I would need to drive this car with a scanner hooked up to say for sure what's going on. A good driveability technician should be able to get a "snapshot" of this thing acting up and tell you what's wrong.