3.2 engine problem

[78-911SC]

After some time away from my project I'm back at it. Here's my problem. The engine starts quickly with the tach going to 1200. Within 30 seconds it starts to drop then it catches itself and quickly goes to 1800. One min. has now passed. Within the next 30 sec. it goes down to the correct idle of 880. Acceleration feels strong but when I'm at a constant speed every 3 to 5 sec. there is a very slight miss. Anyone have any ideas?

Here's a quick overview.
1. 3.2 (88) just rebuilt. (installed in a 70T)
2. New plugs, rotor, cap.
3. New CHT sensor. (2 wire)
4. Sent injectors out & had them cleaned.(RC Engineering)
5. Checked all grounds.
6. Checked full throttle microswitch.
7. ISV was cleaned and has vibration. Switched with a second just to be sure.
8. New 02 sensor. (shouldn't have any effect until warm)
9. Checked for vacuum leaks.
10. Read the searches that I thought would help.

Some thoughts. The vacuum line that goes to the oil filler neck with the by pass valve is capped off behind the throttle body because the 70T doesn't have that connection on the neck. So when I open the oil cap with the car running it stalls. Second is it possible that I made some sort of improper electrical connection during the conversion for the 3.2 that it could cause the miss by way of fuel or spark?

[stlrj]

2. New plugs, rotor, cap.

Sounds like an ignition miss. Try new ignition cables.

Cheers,

Joe
74 911 w/ 86 3.2

[Jeff Alton]

Have the base CO checked.

[MBEngineering]

HI PM me your snailmail add and I will send the test book if you would like it .

regards mike