Originally Posted by DaveW
I wonder if my problem is the accelerator pedal, time will tell.

Well, it is about the only thing left!

My car has a completely different engine (GM Ecotec VVTi), a completely different ECU (MBE) and a completely different map from yours, but the only time I have ever had a problem with the car was shortly after the conversion was installed and the symptoms were exactly as you described:

Originally Posted by DaveW
After about ten miles, the power went down like a slider control to just tickover, and nothing more. The engine started normally and idled normally, but would not rev at all.

The car would run ok but had no power, wouldn't pull anything over a tickover. Turned out that one of the new fuses fitted with the ECU and engine loom had blown from being under-specced, and it was the one protecting the fly-by-wire throttle circuit. My engine wasn't getting a valid throttle position signal so defaulted to a limp mode. Went from a 10A to a 15A fuse and I haven't had any further problem in the last 18 years.

Tim H.
1986 4/4 VVTi Sport, 2002 LR Defender, 2022 Mini Cooper SE