Hello I hope one of you can help me... I have been having a challange with my 1995 Pontiac Bonneville. When the car warms up it starts running rough at different speeds and sometimes the battery guage fluctuates greatly. I have had the Altenater checked and it seems okay. Any help would be greatly appreciated.
Robert

check all grounds, make sure all are good and check the connections at the Battery for corosion

thanks for the tip...I will try that...

I cleaned the battery cables and checked the ground wires... everything was okay. I then took it for a ride and as soon as the car warmed up it started to act up again... any more ideas? I just had the computer module replaced... a mecanic thought that might of been the trouble... really hesitant to take it back to him since he couldn't fix it right the first time...

Well the first garage I took it too... Replaced the harmonic Balancer ... then when I started to take it off the lot it was still running rough... they said they may have to replace a sensor... the looked at it and adjusted it and said it would be okay... On the way home it started to act up again... I didn't feel like the first garage did a good job and my wife suggested another place ... here is what they wrote down on bill
they found cylinder 1 and 4 misfiring Test for spark at spark plugs, found no spark at spark plugs and tips loose in plugs. replaced spark plugs, still no spark. Test coil, coil housing cracked coil not firing, replaced coil. Engine still misfiring. Test Ignition module. Module internally shorted replaced module, retest. good spark. road test. All good at this time.... However on the way home it started to act up again... after the car heated up... (Sorry about the long information just thought it may help)...By the way I really appreciate your help and patience...

Thanks again for your quick response... Is there anyway that I can test to make sure it is the crank sensor that should be replaced?

Your garage didn't mention if he tested the ignition wires. I wouldn't overlook them if its a spark problem. Are they original?
Also bad crank sensors do act up when they get hot.
A mechanics trick is to pour cold water on it, re start the car and see if the problem goes away temporarily. Then you would know for sure if its the crank sensor rather than throwing more money at the car needlessly.
Thats just my 2 cents worth.

Rlilly, we have quite a few members in MI that may be able to help you out if need be.