Quick question for the board. I took the 99 Expy 5.4L (76k miles) in the kwick Car for a normal Oil Change. This time I had them flush and change the Transmission fluid and install a new fuel filter. However, ever since this was done, the truck has had a rough idle and it gets even rougher with light acceleration. Moderate to Heavy acceleration are smoother, but not quite normal. I say not normal, because it seems that the power is down slightly (maybe my imagination). This morning I took the truck back to the station. I had them replace the fuel filter again, in case I got a faulty one. But the problem remained. It is just too much of a coincidence that the truck started running poorly right after a fuel filter change. I put in a can of Berrymans B12 into the gas and have run about half through. Still no change. Running consitantly rough, but never seems to die, even at cold start. What should I do next? The mechanic suggested that I change the plugs, since this has never been done.

Your advice would be greatly appreciated. BTW, the truck has never had a history of any problems. (other than the "normal" right head gasket leak ; )

Thanks for your help
R/
Sbauld

 

I would start by looking for a vacum leak. Train filter change might have knock something loose. ??? Check the top of the engine around the dip stick. Look at the COP to see if one got knoack around.

 

Considering what they did to your truck mechanically, they shouldn't have "messed" anything up. I'd start by disconnecting the battery for 10-15 minutes. This will reset the computer. Then go out and drive as it as you normally do. The truck will act a little funny for a few minutes while the computer reprograms itself, but it should run smoother. If this doesn't help, try pulling some codes rather than guessing.

 

THE SAME THING HAPPENED TO MY 98 EXPY. IT WAS THE #2 SPARK PLUG AND THE COIL PACK ON THE DRIVERS SIDE (THAT ONE COVERS THE #2 CYLINDER). IT GAVE A CODE THE SAID #2 CYLINDER WAS MISSING, BUT I CANT REMEMBER THE P-#.