it would pretty much have to be the TPS in some way acting up. Right? From what IÆve been reading thatÆs the only thing that lets the ignition timing advance. ???
I'm not 100% sure about that, I did read that there are a few timing "stages" that the ECM goes through when the engine is warming, but I did NOT see evidence of that today when I was experimenting.
Books say that below around 70* coolant temp, that the ECM slightly advances the timing for smoother starts. Then, between 70* and 140* it says the timing should retard a few degrees to warm up the cat conv. But, like I said, I could not verify that by what I saw today.
When yer drivin' though, there are other things come into play. Vehicle speed is one of them. I think the coolant temp is another. There are "tables" stored in the ECM with timing curves that it uses to adjust the timing while driving.
One thing I noticed was that when I manually pulled the throttle cable and letting it snap back down sometimes it wouldnÆt go to the stop. So I let abit of pre load off of it by adjusting the little nut/ slider plate thing that holds the throttle cable to the throttle body.
That could well be part (all?) of the problem. There should be a slight bit of "freeplay" in the cable at idle.
...IÆll change out the TPS with a spare I have and see what that does.
Be sure and verify the new one is 100% reliable first, of course. Use yer ohmmeter and make sure both switches go VERY close to zero, EVERY time you turn the switch. If not, might as well go ahead and open it up and clean the contacts before installing it.
Steve, I feel yer pain! I know how frustrated you must be getting... spending all that time and money, and problems like this. ARGHHHHHHHHHHH!!!!!!!!!!!! <img src="/forums/images/graemlins/shiner.gif" alt="" />
