96 Pon Bon Troubles

pontiac
bonneville
sensors

#1

I took my 96 Bonneville to the shop last Friday because the engine light had been coming on and off and it seemed to be missing and sputtering and losing power sporadically. It had gotten a tune-up not quite a week earlier; plugs and wires only. I was hoping that would fix the problem; a parts store had put the diagnostic machine on and said that might be the case.



Anyway, at another shop on Friday, my car was put on a diagnostic machine, while running for at least 25 minutes. They thought they could get an EGR(?) that day, but as it turned out, they could not. (I got there about 1:30 pm). The mechanic said it wouldn,t hurt the car to drive it, but when I tried to leave, it wouldn’t start. We waited and tried a couple of times, and finally after waiting approximately 15 minutes in between trying, it finally started. I was able to make the 17 mile drive home, but the car’s performance was worse than before. I didn’t drive it again until Sunday morning. Before I was approx. 1/4 of a mile down the road, the check engine light started flashing, and the car had a real loss of power. I drove back home, and will take back to a shop as soon as my Mom can follow me to town. Should I have it towed? Do any of you have any ideas that could shed some light on what’s going on with my car?



Isn’t there more to a tune up than plugs and wires? I thought what I paid would have covered a complete tune-up. (I didn’t ask for part of a tune-up.)



Any suggestions would be greatly appreciated.



96 Pon Bon


#2

I would recommend having it towed. Flashing check engine light generally means get towed to avoid engine damage. The fact you only got a quarter mile and back also indicates you might not make it the full distance to the shop. “Tune Up” can mean almost anything. Today, it mostly means plug change. Checking/changing other filters are not necessarily part of the mechanic’s definition. You have to ask. New plug wires on this car is good due to age.

Hopefully, a second diagnostic with the check engine light flashing issue may help the mechanics narrow down the issue.


#3

You mentioned an EGR valve…If that is stuck open, it can cause the problems you describe except the no start…Otherwise, the ignition control module or coil(s) are suspect…


#4

I found the codes that were read at autozone: P0300 & P0171.


#5

You probably have a pretty big vacuum leak or a fuel delivery problem (P0171 is system too lean = too much air or not enough fuel - or maybe both). This is probably the cause of the multiple cylinder misfire (P0300).

You need to check the fuel pressure (how old is that fuel filter?) And you need to check it for vacuum leaks. There is a vacuum schematic on the underside of the hood to help you find all of the line. Also check the big black intake tube for cracks/splits etc. These can be hard to see - pull it off, bend squeeze pull etc.

Oh - and don’t take diagnostic advice from the parts store guys. Just have them get the codes for you and then find out what they mean and how to go about finding the problem (not that new plugs & wires is ever a bad idea).


#6

THANK you for your input. I found the codes that autozone read last week: P0300 and P0171.