Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
Thanks for the reply hardtopdr2.
The reason I think it’s the tranny is because of the jerking at cruise speed and it seems to be happening in the 3-4 shift. Or vice versa. 1-2 gears seem good shift. I changed coil pack and a whole slew of other items. I will eventually get around to cleaning the valves, but I need the tranny diagnosed first. Stay tuned.
Thanks
If you have a scanner with graphing view look at the trans data for TCC solenoid, 3/4 shift solenoid and line pressure data. Also what trans do you have in the van ? 4l80 or what?
I quickly scanned through this post. I did not notice anyone mention Cam Retard. (i am not calling you names, this is really what the PID is called.) It needs to be within 5 degrees of 0. 0 or slightly positive is desired. If its off by 7 Degrees it will miss fire. its the most common intermitten misfire with the GM Flat top Distributor engines. look at your scanner data. To set it you turn the distributor like you are setting the ignition timing on a carb engine. Some are not Adjustable. Most Aftermarket Distributors that are not adjustable will be off brand New. I have never gotten one from Autozone that did not have to be sent back. When your setting it, you have to rev the engine above 2k rpm for the PCM to register it. (snap throttle) As for the odd OD shifting. If seen 3 of these vans that the MAF was dirty/faulty that would cause this. These vans use the Load Percentage from the PCM to determine Shift Points. The biggest contributor to the Load percentage is the MAF.
So the miss I’ve been feeling actually turned out to be the tranny.
When I drive it in 3rd gear the jerking (which I thought was a miss) is no longer there. Also I have had no more engine codes for the past 2months, since I found and fixed the deteriorated/ broken ground wire next to the goose neck.. Live data still shows low counts of miss firing but I think my focus will be with the tranny now.
I appreciate all the feed back I got from this thread.
