ehall

^^^^^^ see above.

Just run your fingers down the sensor wires. Wiggle them. you're looking for an obvious cut. Wiggle it when the car is running and listen. Do that in as many places as you can touch without hurting yourself.
If there is a problem, that should tell ya.

dillon410021

I checked the reference sensor wires and they are brittle and starting to tear and break right at the sensor. On the dme temp sensor, the wires are a little corroded so I will clean them. I will pull the cap off tonight and look at the rotor. < Do you unscrew the screws all the way or is it a half or quarter turn and its free?

spyder348

program maybe with cold start enrichment thing since you have maf? def not 02 sensor even if sensor was bad it would not be that noticeable. Just had a FPR on one of my 944's go out yest. and go out baddd. not that i had a 30 mile drive and maybe 15-20 hp loss. not much stumble. how do you have your maf set up. iat? or is it flattened in the chip program?

spyder348

faulty coil? sensor usually stays bad for more than a mile. bad speed ref. sensor more like a no start.

dillon410021

I giggled the reference sensor wires this morning and it started and ran better than previous days. I will have to order them

ehall

YEP!
This is EXTREMELY COMMON!

There is a bad habit, on this board, of over diagnosing mechanical issues. Always start with the most basic elements.
Sure, there can be complicated problems, but in order to fix those, the basics have to first be solid.
Until you get the sensor wires replaced, be prepared to jiggle the wires reasonably often.
Glad you fouund it.

ehall

For the dizzy cap, check out the write up on Clarks-garage.com.
It can be a bit of a PITA

spyder348

Good diag. to know. Y would it run better after a mile of driving?

ehall

The wires move around a bit. It's basically coincidental. It can also run worse, he's just used to it so he doesn't notice as acutely.

spyder348

Makes sense I wish bad running issues in my cars were easy to get to like that. Could have been worse.

carlege

Surging or stumbling idle is an indicator of problems with the ICV. Problems with the ICV circuit in the DME will only manifest themselves when properly tested. If you think your DME might be at fault. Could be a cooked ICV circuit in the DME? Worth exploring

ehall

He foiund it already. See above.

ehall

The engine bays of these cars are REALLY hot, so all wiring needs to be thoroughly checked. 20+ year old stuff is mostly brittle so there are often a number of similar issues that SEEM like they are something big, but are not at all.

dillon410021

Well I am pretty sure that is the big problem. I will clean and check the ICV when the intake is off next month!

odb812

I'm running about the same setup as you right now with the ape and everything. I had this problem last year and replaced the harness with the LR upgraded harness. Took a couple of hours in a parking lot, not too tough. One problem is that the wires are attached to the back of the intake manifold where the connections are. When the motor torques back and forth, it wiggles the wires back and forth and as they jiggle, the brittle wires break. When I finished mine, I ziptied the wires to the firewall instead to prevent this.

After I did this, my car would start and run but had idle issues. I found it was the ISV by disabling it at the diagnostic port as in the Clark's Garage idle speed adjustment writeup. I have been driving the car for a year now with the ISV disabled at the diagnostic port with everything else in tact, I just have to turn the idle up in the winter and down in the summer.

Don't worry about the O2 sensor. Like I said, I have the same setup and I've used a broken O2 sensor with no wires installed basically as a plug. The car ran rich because it never went to closed loop, but it ran. I would not go out raggin the car with no O2 sensor, but it should still run and drive fine. The back left corner of your car will look much cleaner once you put a new one in though.