Hi, I have a 1989 Oldsomobile Ninety-eight. A couple weeks ago I drove it around town, running various errands, and it ran fine - no indication of problems. Then, just the other day, I had trouble starting it. After a few tries, it started, but then backfired and died immediately. I noticed an unfamiliar odor that seemed to be coming from the exhaust. My first thoughts were, “Somebody has put something in my gas tank, because the last time I drove it, it was fine.” This issue was totally unexpected. All the same, I drove it to the grocery store anyway. As long as I kept giving it gas, it would go, but it died at every stop. In order to take off from a stop, I would have to slam it into gear. It ran fine once I got going. Any ideas as to what could be causing this?
Well, from your description I’d suspect a Mass Air Flow sensor, but any of a dozen things can cause the trouble you describe. You’re going to have to find a shop with equipment and mechanics old enough to be familiar with your car.
I have a 70’s Ford truck that does this from time to time. I’ll drive it once a week or so for months and it starts and runs perfectly. Then I’ll start it up one day, and it won’t even idle without dying. I have to step on the gas pedal just to keep it running, and even then it is surging and coughing. In every case, this has been caused by a vacuuum device or hose springing a leak in the interim. @Watts, do a quick visual of all the vacuum hoses, especially where they connect. Look for cracking, broken connection, etc. Nothing? Then ask your mechanic to check all the vacuum operated devices – like the power brake booster if you have one – with a hand held vacuum pump. If they have sprung a leak, they won’t hold vacuum.