overdrive problems

[scott62]

Ok here we go, 1st thought I had a motor problem, my car started doing this ( chugging thing ) ( studdering ) or as my wife says bumping. You step on it and it smooths out. I thought I had a fuel problem, bad gas or injector but after driveing it awhile I noticed it only did this when the car was in overdrive and under light accelleration betwen 45mph and 65mph once it kicks out of overdrive into 3rd it doesn't do it. If you drive it in 3rd it doesn't do it and if your going say 80 or 90 it doesn't do it. It's a 1995 parkave ultra vin #1G4CU5210SH640000 anyone have any ideas ?

[HotZ28]

Obviously, you have secondary ignition misfire. This problem is usually found in the ignition wires, plugs or coils. Normal troubleshooting procedures should help determine what the problem is.

[scott62]

ok I trust your vast knowlage I've read alot your replys plugs are only 3 months old wires are original as far as i know I've owned this car since 98 I've read that only ome are acceptable for this car? I've changed 2 or 3 coils over the years but they all were obvious visual failures how do i check one if it's not obvious.

[HotZ28]

You should check the wires first, however, when testing the coils primary resistance, use a paper clip (cut in half) to insert into the primary side terminals. (Female - Bottom side of coil) and place the two leads of your DMM on these to check resistance.

On the secondary side, simply place the leads across the two coil output terminals and set your meter for reading K-ohm.

The specs for resistance are:

Delco ignition: Primary (ohms) = 0.5-0.9 (ohms) Secondary = (k-ohm) 5.0-8.0

[scott62]

It was the plug wires. When hot Z28 speaks he knows what he is talkin about. Thankyou