ARDon

Like for ya'lls help on this ........
I have a 1990 GMC Z71 4x4 I had the motor redone, transmission redone.
Motor 383 Stroker
parts listed
MOTOR: 383 STROKER
GM Performance 4 Bolt Main Block notched & bored 30 over
Scat Crank
Eagle Rods
Speed Pro Pistons 975 to:1 ratio
Comp Cam: Hydraulic Roller Xtreme Energy Cam
Heads: Vortec with Comp Springs, ported & polished
Comp Cams Magnum Roller Rockers
Comp Cams Roller Lifters
Comp Cams Push Rods
Comp Cams Double Roller Timing Chain
Edelbrock TBI Performer Alumi High Rise Intake
Holley 670 CFM Throttle Body
7" Super Damper
JBA Shortie Headers
Custom Burnt Chip, by Harris Performance LLC

Now heres the problem.............
In the mornings I start the truck the idle is ruff, after a few minutes (5 to 8 minutes) the idle goes way down then idles high, then back to a very low idle then back up again. then it will idle at a high idle. Sometime it wont even idle. Would like ya'lls in-put "please"?
The motor is real fresh , less than 1500 miles. mildly built , nothing radical



thanks ya'll

06chevy5.3

was it like that after you buil it or did it just start doing that?

ARDon

after I had the motor redone.

06chevy5.3

how is the timing?

ARDon

set @ zero like the chip manufacture asked.
Note* the cam in this motor aint big, slight lope.
Some mentioned to me a adjustable map sensor? what do ya'll think?
I've heard some folks hadproblems with Holley Throttle bodies acting up like this. Have ya'll hear this?

Thanks Don

holyspatulaboy

i had teh same problem... take off the throttel body and there is a plunger in the TB that controls the idle and carbon will build up in there... also while you are at it clean off the butterfly it will look like someone took a crap on it... i just used normal spary can throttle body cleaner and a rag... i do this on a regular basis for my truck every about 20,000 miles... also i run sea foam through the vacume line to also help clean out the intake manifold...i think this comes from the vent case hose blowing oil almost directly on theTB... another simple more expensive fix would be to just change that plunger out... but no use it is still good and will jut happen agian witha new one...