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Buick Jerks

I have a 1995 Buick Lesabre. The car jerks while I am driving or when idle as if it wants to shut off. Sometimes it jerks and then the check engine light comes on. When I described the problem to my mechanic he said that it might have been the fuel filter but then he said it might be an electrical problem. I would like to start with the fuel filter to see if that would help but I am not a mechanic nor am I an expert on cars nor do I want to spend tons of money on such an old car. Any advice would be great…

You don’t replace a fuel filter to “fix” a problem. You replace a fuel filter on a regular basis as part of basic maintenance so that you don’t experience problems. So how old is the fuel filter? Is it due for replacement? If it is due for replacement then replace it. If it is not due for replacement, then don’t assume it is a problem.

The same goes for a lot of other things. How old are your spark plugs and wires, for example?

The check engine light means that error codes were stored in the computer. Did you mechanic read the codes? If so what were they? Auto repair is not a matter of shooting in the dark. If the codes weren’t read, this is a 1995 so it is probably an OBD 1 system, and here are instructions for how to read the error codes:

Again, I don’t know much about cars. I am not sure how old the fuel filter is. When my mechanic tried the diagnostic test he said that there was no reading but the car’s power kept shutting off and on. I am not sure what to take of that since there is clearly a problem or if it means that it is an electrical problem. He did mention that there might be a communication problem from car’s computer to cause it to jerk. Not sure when the last tune up was either. I am the second owner of the car and I have not gotten a tune up since I’ve owned it, for nearly a year and a half.

Ultimately guessing is going to get you nowhere on a car that is nearly 20 years old. Try to record the fault code when the light is on. I might start with a tune up (plugs, wires, fuel filter, air filter, oxygen sensor, etc.) for a bucking concern.

Okay, I’ll start with a tune-up…

I should also mention that the engine light goes off by the time I get it to the shop.

Yes the older cars computer systems while functional were not the easiest to work with. There are scan tools you could buy to read the code or there is a method to flash out the code by shorting two terminals together at the diagnostic connector.

Certain 1995 cars used the newer diagnostic system meant for 1996 and up (OBD-I with OBD-II plug) so it is difficult to say what you have without looking at it.

I posted instructions above for reading the codes yourself. It just takes a paperclip or something similar, and you put one end in the “A” and the other in the “B” and with the ignition on but engine off you count the flashes. You don’t need to know anything about cars to do it, and if you can manage to pull the code it will save you tons of trouble.

The plugs/wires/filters are a good idea anyway - just as maintenance. It’s no different than having to occasionally change out your furnace filter or something.

@rattlegas is correct that in 1995 most cars were still on OBD 1, but some were already onto OBD 2. I’m pretty sure yours is OBD 1 and you would follow those instructions above and your connector will like the one in the picture and the pin diagram.

However, if your connector looks like this one:

  • then you are on OBD 2 in which case, then next time the light comes on, drive directly to any big box auto parts store where people read codes for FREE.

When you get codes, post the specific code numbers. OBD1 is just 2 digits / OBD 2 is a “P” followed by 4 digits.

Thanks Cigroller and Rattlegas

Not to poke the hornets nest (much) but some 1995 GM were OBD-1 with the OBD-II connector only, so it’s possible for an OBD-II scanner to plug in and turn on but not read the codes.

“…some 1995 GM were OBD-1 with the OBD-II connector only”

Well, that’s pretty annoying. In that instance, does the OBD 1 pinout remain roughly the same (and then you can still just short the A-B)? Or do you need a whole different pinout for an OBD1 car with an OBD2 connector?

In the case above it has it’s own pinout and it’s own communications protocol. The shorting of the pins does not work on the OBD-I with OBD-II connector. The only tool I know that communicates with this oddball car is the Tech-1 or the Mastertech.

Your vehicle utilizes the non-compliant OBDII engine management system.

This basically means the vehicle is still OBDI but has an OBDII connector. So you can’t use the method of jumping between the A and B terminals to retreive codes, and a standard OBDII scanner won’t retrieve codes. You need a special adapter with the proper programing in the scanner to pull the codes from your vehicle. Or you need at least a GM TECH II scanner to retrieve codes from your non-compliant OBDII vehicle.


Even though the CEL goes off, that doesn’t mean there are no diagnostic trouble codes stored in the computer’s memory. The CEL is primarily responsible for signaling emissions problems. But the engineers built in extra diagnosis capability beyond that. When you bought the car, you paid for that, so you might as well use it. Ask your mechanic to give you a printed read-out of all the stored DTC’s, even if it is done just by reading the blinking lights and writing the numbers down on a pad of paper. Then if the problem still remains, post those codes in this thread. The experts here know how to interpret them and can give you some further guidance.