I bought my '93 FD last year and replaced coolant hoses, vacuum hoses, replaced fpd, adjusted tps ect.....Its a stock ecm, stock engine, just has a few bolt on reliablility upgrades (fluidyne, downpipe, ypipe)

It runs pretty good but has two problems the main one being the idle surges intermittently (2 out of 3 times) when the engine is warming up. The surge usually is between 1200-1500 rpm, sometimes a little lower rpm but about the same gap. As soon as the engine is up to full operating temperature the idle is smooth and at the correct rpm. Oh and I start the car in gear then lightly blip the throttle once so that the high idle start disengages right away. So I don't think the the surge is related to that.

It almost seems like the ecm is cutting timing or fuel.

the other problem (unsure if related) is that when I am driving the car I notice the car has alot less power with the A/C turned on. Takes more throttle and clutch just to pull away from a stop.

I am wondering if the idle surge has something to do with one of the throttle body adjustments. Is there an adjustment that is only in effect until the engine is up to full operating temp?

TPS was adjusted but maybe just on its way out?

Coolant temp sensor starting to go?

Or just a simple throttle body adjustment issue as I know the previous owner has messed with some of the throttle body ajdustments. The only one I touched was the idle screw inside the throttle body to adjust to the correct warm engine idle rpm.

I will try post a video if that would help.

Thank You.

 

Do you have a check engine light/trouble code?