Feels like I'm loosing power, jerky

[Mfitzy]

Hey everyone, I just purchased a used 2002 Bonneville SSEI with 98,898 mi on it a few days ago. Some problems have arouse that I'm getting worried about. First thing was I knew the fuel gage I knew when I bought it was faulty the dealership said they would fix it if when I filled it up it did not remedy it's self. Now It seems that when I start it sometimes it almost feels like its getting ready to stall out but then other times it feels fine. I'm not sure if it makes a difference or not but the service engine flashes when it feels like I can't get power. While I am driving and I push down the accelerator to pass or to get moving on the high way I get no power and it sputters almost but then runs fine if im not pushing down very much. My other issue is that At 68-70+ Im getting a vibrating in the whole car its not terrible but it is definitely noticeable. Thank you for any help you can give I just want everything to run as it should!

[Mfitzy]

I'm thinking it is my fuel pump and filter, could that be causing the power issue?

[nos4blood70]

Sounds like a bad cat if you ask me. Get under the car and tap on it with a hammer or wrench, if it rattles it's bad.

The vibration at highway speed is a common issue among the 2000+ Bonnevilles. You can try a road force balance to help remedy the issue.

[Mfitzy]

Thanks for the response, I just ran out and got a wrench and tapped for a min or so and no rattling. Also as embarrassing as it is After I had picked up the car things got chaotic, and I had to make a trip back and fourth about an hour and a half and I was not thinking and since my fuel sensor is bad I ran out of gas....I know, I know but the power issue was not really there until after I ran out, so I'm thinking maybe the pump was going bad and the filter was clogged and then when I ran out of gas it may have just sucked up all the bottom crap?

[nubuilder]

I'm not sure if it makes a difference or not but the service engine flashes when it feels like I can't get power. While I am driving and I push down the accelerator to pass or to get moving on the high way I get no power and it sputters almost but then runs fine if im not pushing down very much.

Replace plugs and wires. Easiest and cheapest to start with. Besides, if the plugs have never been changed, they should be anyways.

Mine did this when I bought it too. It was fine cruising, but the least bit of acceleration would cause it to hesitate. I ended up having 2 plugs that were non-existent.

BTW - a flashing Service Engine Soon is never good. Do not drive the car more than you have to.

[sandrock]

Flashing service light means there's a misfire and the PCM detects it. Most of the time it's in the ignition system. New plugs (not platinums...either copper or iridium), new wireset. If that doesn't help, next swap around the coil packs. If the problem moves, it's a bad coil pack, if it doesn't it'll be the ignition control or a physical problem that's causing the misfire like an internal coolant leak.

[Mfitzy]

Thanks everyone for the suggestions, I dropped it off today at the dealership to have them fix anything that has come up as I just got it about a week ago. So im sure I will hear back from them by tomorrow. If I can get whatever is going on fixed for free im going for it, I would hope they end up replacing the plugs and the few other things I know are wrong. I will let everyone know what happens, thanks again very helpful information!