Fuel, Ignition or vaccum issue?? Help please...

[rgdtoo]

I recently rebuilt me 85' 3.2. Was running fine until the clutch release fork cracked due to my haste not waiting and replacing the fork during re-assembly. So I pulled the engine/transmission replaced the clutch release fork and re-assembled everything.

Shortly after the reassembly I noticed the car acting funny, like it wasn't getting enough gas. It would run fine then stall out, I would have to rev it to get it going etc, I was thinking I had some bad gas maybe so I made sure to burn off all old gas filled it and ran some injector cleaner seemed to be 100% until it started acting up again. This time during a track event a Laguna Seca Raceway. BLABLABLABLA.....

Symptoms...
Runs fine for a while then looses power like its not getting fuel or maybe an electrical issue. Sometimes when I come to a stop the idol will fluctuate up and down from about 1 to 3k RPM. That lasts for 10 maybe 20 sec until it drops to a normal idol.

So far I have replaced the gas filter which did zero to fix the problem. Any suggestions?

[kidrock]

Cylinder head temperature sensor. Next time you have the issue, have a bent paper clip ready and jump the female end of the sensor connector. If your idle smoothes out, you've found your issue.

[E Sully]

There is also a filter screen in the tank that may need to be changed. Pelican Parts - Product Information: 911-201-141-00-M100
A quick check for vacuum leak is to see if the idle drops when you remove the oil cap. If it does not drop there is a leak.
If you have the old style single wire CHT, the newer 2 wire sensor is recommended. I believe if it is failing or the O2 sensor is bad the car would run rich.
Have you adjusted the throttle linkage and checked the adjustment of the micro switch and wide open throttle switch?

[rgdtoo]

kidrock, E Sully, Thanks for your input.

Pulled the oil cap and the idol dipped a bit so it doesn't sound like a vacuum leak.

Have not adjusted the throttle linkage or checked the micro switch or wide open throttle switch basically because that's all new stuff to me. Guess it's time to learn again.

My car sat for a couple three yrs before I rebuilt it. I am thinking I should pull the gas tank and clean it out. I can change the filter screen at the same time.

I might as well replace the CHT too.

I had my O2 sensor checked while getting the car to pass smog. It was ok at the time it was checked so??

[rgdtoo]

Have not had time to check things yet, this weekend...

Trying to figure where to start though.

As far as the sensor jumping goes would I be right in assuming I could jumper it first then drive. If it does not happen then I found the problem?

Filter screen in tank. Would that be an issue under load only??

[T77911S]

depends on how often it happens. does it do it every time?

i would go back and check your connectors and make sure everything is plugged in. also check for air leaks.

[kidrock]

Like T77911S stated, make sure each of the 3 connectors at your sensor harness are connected properly. The top (white) connector is your CHT sensor.

Start car as normal. If your problem is the CHT sensor, you probably won't notice any immediate surging until car is warm. Pull the white head and jumper the female connector with the U-shaped paper clip. If your engine functions normally after jumping, then replace the sensor. If not, then you have another issue.

[E Sully]

Intermittant problems can be very difficult to fix. I would think a failed CHT or O2 sensor would be an overly rich mixture at all times. Possibility of poor solder joints in DME or DME relay, coil, or fuel pump on edge of failing could show under higher load.
The filter issue could definitely be under load only. The amount of fuel needed at idle is minimal and a partialy blocked filter could flow enough at light demand, while the restriction could be enough to cause starvation at high load.
Work on the cheap and simple items first, especialy neglected maintenance and standard tune up items first before spending money on expensive items.