TPI Cold Off Idle Stumble

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Aug 28, 2003 | 04:17 PM

Ranbo108

Thread Starter

Junior Member

Joined: Apr 2002

Posts: 33

Likes: 2

From: Glen Burnie, MD

Car: '85 Z28 TPI

Engine: 305 F vin

Transmission: 700

Axle/Gears: 3.23 posi 10 bolt

TPI Cold Off Idle Stumble

I am new to TPI. My '85 Z-28 has a bad stumble off idle when cold, even when I'm gentle. Once warmed it runs great. 180K easy miles with mostly original parts. Is this a well known or common problem or maybe a combo of issues? any thoughts?
Thanks, Randy

Last edited by Ranbo108; Aug 28, 2003 at 04:40 PM.

Aug 29, 2003 | 07:52 AM

Vader

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Joined: Jan 2000

Posts: 19,675

Likes: 314

Some throttle tip-in hesitation is to be expected, but it should almost be unnoticable. Things that will exaggerate the hesitation are a low TPS voltage setting, a throttle minimum air position setting that is too low, low fuel pressure, external vacuum leaks, a sticking or leaking EGR valve, sticking PCV valve, or base timing setting too retarded.