I just bought a 2000 DX from a friend (I knew the car had issues when I bought it). Basically the car seems to run fine while cold, but as soon as it warms up it runs very poorly. Low/almost no power, stumbles and misfires when giving it gas off idle. It will struggle/stumble for a while but will eventually rev, but only when in neutral/park. Any actual load on the motor and it won't rev at all.

I haven't really dove into it yet, but I'm wondering if anyone can give me a place to start? I know the ignition coil has been replaced a couple of times with a cheap autozone part. I'm hoping that maybe it's just that. Or perhaps a coolant temp sensor? Am I correct in understanding that there are two sensors? One for the gauge and one that goes to the PCM?

Any other ideas/things to look at? Going to do a full diagnostic on it tomorrow, fuel pressure, compression test, leakdown, etc etc.

 

could be the temp sensor near the distributor going bad.
it runs to the ecu and eventually creates a no start when warm deal.
just replace with the ntk unit it's cheap.

 

I was thinking that. I thought the single wire sensor (the one under the distributor) was for the gauge, and the two wire sensor that's in the thermostat housing was the one that went to the ECU?

In either case, my scan tool shows that the ECT is reading normal. Showed 86 before I started the car, and climbed pretty quickly (maybe too quickly?). Not sure if it's bad, but I'll probably just swap it out anyway once the car cools down.
I replaced the ignition coil since I had one laying around and the old one was super corroded. The stumbling seems less worse, if I gently give it throttle when in Park/Neutral it revs just fine. If I try to give it anything more than 20% throttle or so it misses like crazy.

Edit: So when I was replacing the coil, I noticed the rotor and cap looked pretty worn. I limped the car to the autoparts store and bought new plugs, wires, cap, and rotor. Car runs like an absolute champ now. Have to do some driving to make sure this really solved the issue, but so far things look good!

 

Nope... that is the "Fan Switch" which turns the cooling fan on when it senses the proper temperature. The ECT is very close to the single wire sensor that you spoke of for the temperature gauge on the instrument cluster. The grey plug that connects to the sensor has TWO wires... and the wire colors are Red/White and Green/Black.