I'm really scratching my head over this one, - I'm hoping that someone might have an idea about this!

I've got a Mk3 Escort 1.6i that I've converted to EFi. I've changed the entire loom to one from a Mk4 Efi one, and I've replaced the old MFi head and inlet manifold with the EFi one. To get around the CPS problem I've used a 36-1 trigger wheel mounted onto the original front pulley, and a pickup off an 1800cc Sierra. It has a 1AFA ECU fitted with a superchip.

The car starts perfectly, and seems to run OK. But it is down on power and doesn't seem to want to rev up past about 5000RPM. I thought this might be my imagination at first but I had the car put on a rolling road,
and peak power was 96.9BHP @ 4920 RPM and 105.8 lbft @ 4050 RPM. After 5000 RPM the power dropped off rapidly but the car doesn't misfire - it just seems to hold back. When it was on the rollers the lambda reading was around 0.75 which is apparently quite rich. But when the operator checked the mixture at idle the CO reading was about 0.3% which is lean. He also noticed that someone has been playing with the fuel pressure regulator as the cap was missing.

When the car is cold it seems worse. It will start fine and run OK, but if you try and pull away quickly it seems to hold back at about 3000RPM, but this clears up once the car is warm.

I have swapped the EDIS, MAP Sensor, TPS, Fuel Pressure Regulator and mixture adjustment pot, none of which makes any difference. I have removed the superchip and it is exactly the same. I've tested the resistance of the CTS and the ATS and they seem reasonable. The CTS reads about 22k when the engine is cold, and drops to about 4k when it is
hot. I have tried running with the CTS and ATS disconnected and the problem is still there but it seemed to hold back at about 4000RPM rather than 5000.

I've used a fault code reader to put the engine in diagnostic mode, and checked the timing with a lamp. It is exactly 10 degrees with the octane adjustment lead disconnected, which I think is correct. I've checked the cam timing and both timing marks line up correctly. The car does not log any error codes in the ECU either.

If it was always holding back at 5000RPM I would think perhaps the camshaft is worn, but I think it unlikely as the engine is fairly quiet - there is a slight tapping at idle but nothing major.

I suspected the CTS, but the readings I've done seem to indicate it is working, and it is worse when it is disconnected altogether. Do these get inaccurate when they get old or just stop working altogether? I imagine they probably just stop working.

The only other thing I can think of is the CPS, - but I think it runs too well for that. It doesn't misfire or hesitate it just doesn't want to rev up...

Has anyone got any ideas because this has got me completely stumped.
Thanks for any suggestions you can offer!
Mark