I have a '93 with two problems.
1. When started cold it goes through all the proper idle routines. However, when you go to accelerate it hesitates. If you let of the gas it will recover. once it warms up it runs fine. It still gets great in town and highway gas mileage. I simulated the condition in the garage with the hood up and it appears it is getting too much fuel when I hit the accelerator.
2. After driving on the highway for an hour or so, the engine will start to stall or miss. The cure seems to be to let off the gas, put it in neutral, turn off the cruise and let the speed go down to 60 and the engine to be at idle. Once you do this the SES light will go out. Then you can go back to cruising speed and all is well for 15-20 minutes and then you start the routine all over again. I have replaced the oxygen sensor twice, because that is the code that was set. I made the second replacement because I thought I had gotten a bad one. Still have the problem.

Thanks for your help.

Are you still getting the code for the O2 sensor? What brand did you buy. If it'* anything but an AC/Delco, or Denso - that could be part of the problem. If they were Bosch or Borg/Warner, those have been known to not work well in the Bonnevilles. When were the plugs and wires last done? What plugs and wires did you use, if they were replaced. Also, check for any vacuum leaks at all the hoses and fittings.

Welcome to the Bonneville Club.

Both replacement O2 sensors were not AC/Delco. I have not changed the plugs or the wires.

OK, why don't we start there? Get an AC/Delco O2 sensor, and new plugs and wires. Our cars go through Bosch plugs very quickly, so stay away from those. Many like the AC, NGK, or Autolite plugs. NAPA Belden wires are also a favorite.

This sounds like weak spark to me. Slight possiblility of a vacuum leak.

it might be a fuel pump, sounds like a problem I had on my '92 SE and thats what I did and it fixed it

Hi Marathon.
My SSEi was experiencing similar problems, turned out to be a weak coil pack.
Maybe check this link out supplied by Mr Wren, and see if it applies to you.
My car ran fine, until it was under load, and I punched the throttled.
Following the details in the link pointed out the problem. For me, one of my coils was mal-functioning. I changed the faulty coil, punched the throttle, and peeled off a better portion of the life span of my tires. :P
Let us know how it goes!

Adam

http://www.bonnevilleclub.com/forum/...e=article&k=33

Sounds like a possibility. I will check it out. On an AC/Delco, am I checking from plug terminal to plug terminal or plug terminal to ground? The picture seems to show plug terminal to plug terminal.

Thank you for the advice.

PS - I have already check for vacuum leaks and found none.