99 grand prix strang issue

**Machzzzz1** · 12-31-2012

So my prix was running excellent until I stopped at a gas station. I put $20 bucks in and when I went to go I turn the key and the engine starts fine but the moment it settles down it starts to run rough and seems like its down two cylinders. It sounds like a 4 banger and makes no power. It's sluggish to rev in neutral as well. If I shut it off and restart it, its fine and I can rev it normal for about 5 seconds and then the engine starts to run like crap again.

Any idea where to start?

Thanks

**Sven the Sexman** · 12-31-2012

Fire...that's all that will fix this problem. But seriously, you could've gotten bad fuel, cat clogged, ignition system/fuel pump issues...it could all be coincidental, or it could be related to the fuel you put in. Kinda hard to say. Any extra details about the car ei. engine, modifications, etc.?

**vandezand** · 12-31-2012

could it be that they are supercharged and put some 87 instead of premium 91?

**Scottydoggs** · 12-31-2012

not likely if its a on / off again problem.

could be anything like listed above. start with checking the icm ground, and the main grounds and clean the battery terminals.