swaycleveland

ok all you wizards out there!!! as of yesTURDday my runer started idling rough here the the question ive got it down to a vac type problem but this is odd i took the vac line off the brake booster and BAM the truck runs like a top!!!! i mean awsome so which problem do i have i have taken the vac line off the TPS and the truck idles higher but not right some im thinking the TPS is work fine anyone got a clue why that hose makes everything better
????

swaycleveland

it seems that anytime a TAKE OFF a vac line going to the manifold the truck runs better help???

mt_goat

Good question, but bad title.

I could see that happening if the engine is running too rich. Pulling a vac line off would cause the engine to run leaner because unmetered (and unfiltered BTW) air is being sucked into the intake.

I'd look into what would make the engine run too rich. I'd check things like the O2 sensor, AFM, cold start injector, fuel injectors, air filter, fuel pressure regulator, etc...

swaycleveland

well i can tell ya that its also hard to start if i pump the gas it starts and from then on ( with a vac line off its fine) its not throwing any codes o2 and fuel reg are fine just changed them

thook

I think I'd run a test on the air idle control valve.
http://www.autoshop101.com/forms/h60.pdf

mt_goat

So have you been driving with the vac line off? If so, the ECU has been using the O2 sensor to adjust the A/F ratio. It will try to keep the ratio at 14.7 and over time it will change the fuel maps trying to keep it at 14.7 with the vac line off. Then when you put the vac line back on, the fuel maps will be wrong. To reset the fuel maps back to the default settings pull the battery cable for a while.

swaycleveland

iac hmm interesting i went to a local dealer today to find out how much they charge for a diag test 95 bones and they can tell me what it is however after telling them what ive tested so far the guy says hang on got a mech and we told him he said to check that also thanks for the link i was just looking for that

swaycleveland

goat thanks for the info i was wondering if i might have to reset things to normal

thook

Those things are funny....ECM's. I mean they're doing what there supposed to be doing, but sometimes you think you've fixed something when CEL doesn't come back, the ECM has to readjust to the hopeful fix, and then a few days later the stupid light is back on. Should stand for Eternal Circle of Madness.

swaycleveland

my cel hasnt come on ever lol

thook

That's nice.......me< >you

swaycleveland

lol so after all this work and by work i mean reading threads on the puter im thinking that its the TPS even though i did do a check on it im thinking it has failed its the key item to my fuxuating idle