I have had problems with the engine running rough for 6 months now and my gas mileage sucks. I put new spark plugs and I also bought one coil and slowly moved it to each cylinder to see if it made a difference. No difference.

I also had a vent issue where it would only blow defrost. Then my auto hubs wouldn't lock in. I sprayed all the lines down and cut a hose and reattached it where it was warn. That hose is the one that goes to the passenger side engine and has a coolant hose running into it. The circle metal piece seems to be just sitting in the engine. Now it is not running rough like it used to at idle. My hubs and vents work now as well. My exhaust doesn't smell any more ether. (IM GUESSING it will be temporary).

The one problem that didn't go away was the rough running at 1500-2000. I do still here a hissing sound coming from the top of the engine but i cant pin point it. It sounds like it is coming from the IAC.

Any suggestions?

 

Sounds like you still have a vacuum leak.....or intake/gasket issue.....don't know what the V10 is prone to.....you might want to post in the v10 engine section

 

Could possibly be a small electrical system?

 

Moved to the Modular V10 (6.8L) forum.

Stewart

 

I will try the replacing the gasket and see what happens.

 

After all that i decided to replace the spark plugs and the third one i pulled out was bent in so there was no gap. No the truck runs great. The guy who installed them must have bent it while installing.

 

I don't know how someone could manage to hit the plug hard enough during the install to close the gap. Half assed mechanic I guess. Good to hear you got it fixed.

 

Yea i know. Im just glad it was something small.