87 wont stay running......

[outlaw22]

I have a issue with the car, it wont stay running. If I stay on the throttle, it will surge.
the problem comes and goes. sometimes it will work fine for 1-2 weeks, and sometimes I cant get it to hold a idle. Starts up every time, but wont Idle, just shuts down
Note.. Running big Stuff3.
no vac leaks
no EGR
lots of fuel
I have changed the IAC

Its almost like there is a vacuum leak.
Any Input would be appreciated.

 

[outlaw22]

I do not have a MAF sensor..

 

[GNVenom]

Check the line to your MAP sensor. Even the slightest leak there will cause a major idle fuel problem.

 

[outlaw22]

Check the line to your MAP sensor. Even the slightest leak there will cause a major idle fuel problem.

Data Logged while it was happening . Nothing abnormal on the CPU as far as vacuum signal.
I went ahead and checked all the lines again. (Break Clean). Nothing....

 

[GNVenom]

PCV valve slipped out?

Crank sensor moving out of its interrupter?

 

[outlaw22]

So I checked the PCV valve. Seem OK
Also replaced the crank sensor.
I haven't had any issues yet. But this issue is intermittent.
I think if it happens again I'm going to change the module.
I cant think of anything else it could be.
Note: this would happen once in a blue moon before I installed the Big stuff3.

 

[outlaw22]

BTW THANKS for you input.