Engine/Transmission (1998.5 - 2002) lift pump and fuel economy

[RJPotts]

Lately my mileage has gone downhill pretty severely. I ruled most things out:

new air filter (BHAF), new mopar/cummins fuel filter, MAP is good, cleaned IAT, reset APPS, changed oil, tires pressure is correct. Truck runs as good as ever, no difference in power. I can still get boost up to 33psi or so. EGT's are normal (1000 max pre turbo). I have a FP gauge but it doesn't work right and I haven't gotten a chance to bleed it yet (isolator). Its been low, but hasn't dropped to zero that I've seen.

Any ideas? Thanks in advance.

-R. J.

 

[HookMeUp]

I have the same problem, happen to check for codes last week and got the 0216 code indicating a bad VP44. I take the truck in tomorrow to have the dealer check it out.

 

[nps]

May be time to change the IAT. I cleaned mine - no difference. Changed it and smoke was visibly reduced.

 

[Graphic man]

did you replace the map?

 

[RJPotts]

I did replace the MAP. Didn't replace IAT.

That's just the thing, I cleaned it and smoke went away, before if I would lug it the slightest bit or roll into it harder than necessary it would blow smoke everywhere, now I have to try and its not thick black smoke, its more the color of the haze you get after boost comes up. I'm taking it to the dealership tomorrow I'll let them deal with it.

Then I'm getting a 12 valver.

Any other ideas, keep 'em coming.

Thanks,

-R. J.