idles fine and smooth even at 500rpm (in gear) If I idle it at 800 then it hits a little hard with this tight converter. I'll jack it up and see about the brakes, but they replaced both calipers before I boght the truck since it was pulling hard when you hit the brakes. I actually talked the dealer into putting on new rotors and calipers, not bad for a 9 year old truck the dealer wanted to get rid of

I doubt it is an injector, runs too smooth at all rpm's, but again I guess it could be.

Now, yesterday I went through and tightened all the clamps on the pressure side of the air system. none were terribly loose, but I tightened all of them some. It didn't make much difference. Right now I have me plate slid back and AFC pretty tight. It will hit 1200degrees without ANY black smoke at all, I think this is pretty high EGT's for no smoke, whatya think?

Thanks for helping me figure this thing out guys, I'm trying to get ready for this trip, so of course I'm a little nervous.

George

 

Yes i replaced the calipers (raybestos) and i also used raybestos quickstop rotors (drilled and slotted) couldn't ask for better brakes!

hope this helps

Curtis

 

I'm betting on a fuel or air issue. A drop in milage like that and that suddenly makes me think this.

 

how far back is your plate? did you mark the stock position when you put the new one in? is it in the stock position? i have a ground plate. very similar to a 10 but the hook at the top is shorter. with my plate 1/16 away from full forward and my afc full forward i can peg my egt gauge on longer full throttle pulls. that's running about 34 psi boost. my OPINION is that if you're running stock timing you'll see higher end egt's with the plate you have and lower fuel mileage. someone please correct me if i'm wrong. my truck barely smokes. just off idle it leaves a little cloud but leaves a decent haze at full throttle pulls. but 1200 on urs isn't all that high if that's as high as it goes. guys i've talked to with similar set ups as mine but with modified timing are running lower egt's than what i am and are getting better mileage than i am too.

if you've done all ur filter and prefilter work then the only last thing i can think of is the overflow valve may be getting weak and letting more fuel than normal return to the tank. i.e. ur i/p isn't getting full fuel pressure.

it's hard to keep track of things when you do a few mods all at once.

have you noticed a drop in boost psi at all?

 

I mess with the plate so much I can't say for sure how boost has been. I will say that in it's current configuration it will hit 30psi boost at full throttle. It is sitting at pretty much the stock location. I usually run it pretty far forward but moved it back cause EGT's were too high and I was loaning it to my kid brother to drive to Denver and back and figured to keep him out of trouble by restricting his power a little

I'm going to try to open up the exhaust a little bit and maybe order a new overflow valve, then see how it works then.

Thanks for the help on this guys,
George

 

Any luck on figuring it out yet George?

 

Just got back in from vacation and apparently it was a simple matter of my truck being possed by demons and an easy excorsism has it fixed.

Seriously though I have no idea what was going on. I drove 2411miles last week and averaged 19.6mpg for the entire trip. One leg running 65mph got me 24mpg and the return trip running a steady cruise control 83mph was still getting me 600 miles between fuel stops and averaging 18.9mpg at those high speeds.

So, to sum it up I ain't got no idea what was going on, it lasted through three tanks of fuel getting 15-16mpg and then suddenly rose back up to around 20mpg with the same ULSD so I dunno.

Thanks to all those who tried to help me out though and look for a trip report with pics sometime towards the end of the week.

Thanks,
George

 

could they possibly start putting summer diesel out and not blended anymore?

 

I had thought of that before, but I've gotten 24.6mpg on winter ULSD and 16.9mpg on the same at the same speeds. The trip I took started off with winter ULSD and got me 18.9mpg at 83mph and my return trip was with summer fuel and netted 19.8mpg at the same speeds, so not much difference. One day I'll understand it all, but for now I guess not.

George

 

A long trip may have just burned some of the crusties out of it and loosened it back up. Glad to hear it's back to normal though.