Two different motor management systems (actually three). Cold motor, hot motor (operating temperature around 140-160 or above) and full throttle.
If it happens on both a cold motor and a hot motor, that eliminates some senors as being the cause. Sure sounds like a warm motor O2 sensor issue, have you checked the O2 wiring harness where it runs up the front of the motor for burn marks?
so the plug at the o2 sensor is all melted looking, the harness side. So we should replace that part of the wiring harness. Ill look into the rest.
Plugged CAT is a possibility. Plugged fuel filter is another or something with the pump and/or pressure. I've driven around with a fuel pressure gauge taped to the windshield wiper just to eliminate fuel as an issue. I had a similar issue once when my ballast resistor was failing.
so we can unbolt the exhaust right before the cat and see if it gets better.
went to change fuel filter and fuel was spraying out everywhere right after shutoff. We didn't change the filter, so even if pressure at the rail is good the filter could still be clogged? Ill make sure we change it asap.
I had the same situation when I installed my distributor one tooth off. Idled fine, but would run out of timing advance at higher RPM's.
we haven't touched the dizzy since we got it. Not sure .
Adjusting the TPS is just the half of it, the ground has to be good and the wiring to the ECU from the TPS has to be good (low ohm). The TPS has alot to do with timing.
tried a brand new TPS and multiple spares and it . I checked the ground first thing, no resistance. Ended up putting the brand new TPS back in. output 17% of input voltage every time. grounds are legit. (since its manual)
Check your CPS and the CPS wiring, it doesn't sound from your description that this is the issue, but I doubt I've seen every possible scenario. I do know the CPS often gets worse as it heats up. Mine ran pretty bad once as the CPS wiring was slowly cooking on my exhaust manifold, it got progressively worse as the wiring melted.
CPS seems to have a jumper wires straight to the ECU, hard wired in, no connector. We have a brand new one to go in. need to swap it to rule it out. I will have him check the wiring. ill need to look into that.
Weak spark can hurt higher RPM performance. It usually shows up as a bad idle and/or a idle with an occasional miss at idle and then the spark breaks down again at higher RPM's. Seems the motor needs a hotter spark at idle and at higher RPM's than it does below peak torque (around 2200 RPM's or so).
Just on a hunch check the vacuum line for your MAP. Run your finger under the vacuum line and feel for rough, rubbed or chaffed spots.
first thing I checked a few months ago. that line was cracked. replaced it immediately.