Hey guys...need some brainstorming help.

I posted an "intro", but in case you missed it: I have a used ITA S13, with a SOHC KA that has required a headgasket, new bearings, new injectors, and many cleaned up plugs (for sensors).

It never felt like it made power above ~5000...it pulled great until thereabouts, but then just stayed flat.

It's taken a lot of work, but I got it running *perfect* a couple weeks back - I did a "redneck dyno" (quarter mile), and it trapped 84.4mph...which would estimate 130RWHP given a weight of ~2800 with me in it.

It ran it's best that night. Pulled hard and strong until redline.

Took it to the semi-local short road course (Gainesville Raceway), and it was flat again? I thought maybe it was the heat, but the data shows a max speed of ~68mph on the back straight - I should be doing around 74-75mph, easy...even in 100F weather. And again, it had no pull over 4500-5000rpm.

This was 2 days after it ran perfect.

I have to think it's a sensor, or wiring: MAF, TPS, Coolant temp...one of the ones the ECU would use to determine load and timing advance.

Maybe fuel pressure, but I don't think so...it's got a fuel cell with a Bosch pump.

I think it's a poor connection, or intermittent short.

Here where you come in:

Have you ever been to the track, and had your KA24E feel down on power...only to find the CTS plug had come loose?

Ever had a bad TPS, and the car ran...but felt slow?

I've tested all these sensors at idle, and they all check out. CTS resistance is good, within spec for the ambient temperature. TPS shows ~0.5v with the throttle closed (idle), and +4v with it WOT.

Base timing has been checked and checked again, and it dead-on at 15 BDTC.

Maybe a bad distributor, or more specifically...a bad crank position senor within the dizzy?

Give me some ideas, please.

I feel like I've checked and double-checked everything...this is my 11th 240SX, and I had to do my fair share of troubleshooting over the years.

But on this one, I'm stumped.

Thanks for any suggestions.

- Brian