Rough Idle and chocking at steady speed

[Iytchy]

I have a '96 Bonneville that has started idling rough lately. Figured it was plugs so I changed them out. Didn't help. Wifes car needed new fuel filter so I decided to change mine out too and see if that helped. After changing our the filter I took it on a trip. (this was the same day) Ran fine all that day. The next day I came home and that's when the trouble began. The rough idle is worse now and actually acts like it is going to choke out completely. Also, and this is what has me confused, at a steady speed on the highway it stutters. Usually happens when I am cruising at a steady speed. If I get on it, it clears up and gives me no problems until I get back to a steady pace. Before I fork out some dough to a garage I would like to see if it is a problem I can handle. Any ideas? Oh, and no check engine light and gauges are fine, except the tac jumps up and down when idling rough....of course.

Iytchy

[CarSuperfreak]

the 3800 series engines tend to be notorious for needed a fuel pump replaced. I had mine replaced last year ('95 Bonneville), and I have seen many other people who needed thiers replaced as well. this is not cheap, it cost me like $400, but cheaper than the dealership cost of about $800. The only other thing you may want to investigate is whether all your coils are working properly.

[Iytchy]

CarSuperFreak,

Thanks for the input. I guess what baffles me the most is that this happened shortly after changing the filter. I thought maybe the air pocket in the line might have thrown off a sensor. I went through and disconnected my sensors (one at a time) and let my car idle. Correct me if I am wrong, but shouldn't I get some sort of light, ses or check engine, when sensors are disconnected? None came on. Well I guess I am going to have to fork out some cash and have the fuel pressure checked then go from there. Any other feedback from anyone is greatly appreciated.

Iytchy

[supercharged gt]

had that happen im not saying you have the same prob. but i lost a coil on the highway and was running on 4 cyl.

[tbacusjr]

I'm by no means an expert (for proof of this see my post on a catalytic converter), but your problem sounds suspiciously like the one I just had. A vacuum hose had come loose and caused the problem you describe. The vacuum that was losse is under the plastic cover on the right side near the top. Check to see that the hose is not loose.