Part throttle hesitation or miss, optispark problem?

[aroethli]

The temp sending unit in the pass side head doesn't give any imput to the PCM. It's broken or not hooked up on about half of my cars. I've noticed no difference in how the engine runs.

Fantastic, thanks for the re-confirmation on this point.


So I replaced my TPS over the weekend since it is a $25 part, and as I mentioned, at 160k miles it probably is just good maintenance.

Unfortunately that did not cure my knocking problem. It did seem to reduce it slightly, but the ambient air temp was cool (~65F) but the engine had been heat soaked. So I suspect the TPS was worn and a new unit was a help, but will have to look eslewhere for the actual problem.

I think I'll replace the EGR this weekend as that also is an inexpensive part that at this high mileage is due anyway and will report.

Al

 

[DirtyDR]

I took a road trip out to Moab, about 280 miles each way, and it seems to be running real well now. Once in awhile it still hesitates so I am going to replace the EGR valve also just because but it seems that the TPS was the major issue on mine.

 

[G-699380]

4) Could this be another problem that is causing the optispark to have issues, or appear to?

The optispark is a sealed unit behind the water pump with two moving parts and tolerance designed to last 300,000 miles.

With 160K, you need to replace your plug wires, if that's not in your records. It's not easy, takes two people and a lift, costs $500. And you have to check all NINE wires are replaced and snug.

I know this because I had various suspisions about ignition gremlins. Finally got stuck on the side of a mountain with no tools, no time and no parts.

I mean to say, do this FIRST just because you must, then worry about opti spark.

I hope the wires resolve your problem.

I had that problem and it was the coil wire was lose and old on the opti spark side of the wire I replaced the wire and the problem went a way I carry a spare so I don't get stuck somewhere.