WhenI switched over to a Fastman 52 my truck idled like crap. I shut it down, restarted and it idled a little better but it still took a few minutes to normalize. In my opinion now would be a good time to check your TPS voltage and mod it if need be. I know mine was way off after the Fastman install.

 

I pulled the fuel rails and injectors but they all looked pretty clean. They're getting a solvent bath right now, but I've almost exclusively used Chevron mid-grade or better. Hopefully this is the answer, but at this point i'm a little skeptical...

 

I finished installing the Hughes plenum and 180f thermostat about 3 hours ago. My truck is a 01 5.9. Everything seems to be running very smooth. Maybe the TB is your problem or the computer is having trouble adjusting.

 

I doubt youll see any difference... cheveron is my 1st choice on gas. what was the conclusion on the distributor?

 

I don't think there's anyway my distributor was rotated inadvertantly. I wasonly back there to remove and reinstall the cap andeven when I was trying trying to spin thedistributor, i really had to yank on it.I replaced all the injectors and fuel rails with new o-rings and I'm rerouting all my plug wires as per the TSB relating to the matter. New plugs are in, I just need to find a few minutes to clean my TPS and IAC and then reset my PCM and hopefully that will do it. Keepin my fingers crossed.

 

the seal on the rear edge of the intake manifold is easy not to get air tight when re-installing

 

+!1 on what HankL wrote. I had a devil of a time setting the intake back on without moving that rubber gasket in the back. Probably should have held it in place with some Hi-temp RTV looking back on it. If you can reach back there, you can squeeze some permatex ultra black on your finger and smear it on the gasket.

 

You know, I had a sneaking suspiscion all along that I was gonna be pulling that manifold off again to find this gremlin. You guys might be on to something there. I get off shift 6 am tomorrow and then I'm off for several days so hopefully I can get'r beat. I sure appreciate all the responses I've been getting on the subject.

 

I never use the end seals. A 1/2 thick bead of RTV works best IMO.
Put a dab of RTV in the corners where the intake meets the head/block too.

 

Really? Just slap down a bunch of Ultra Black eh? hmm, that doesn't sound totally crazy.I thought those rubber seals were a little pathetic looking. The little dowels on the seals didn't even line up with the dimples in my block, I ended up cutting a couple of them off. Second opinions anyone?