89 pickup 22RE manual 4X4. I've been having intermittent check engine light problems with this for a while now, when it first started happening it would actually cut fuel momentarily under load so I ordered a remaned AFM from rock auto and installed it. Everything was fine for a while but now the problem is back except it seems to happen while decelerating with the truck in gear mostly and I haven't had it cut fuel yet. I've check the connection and the truck side of the plug is clean and I put some dielectric grease around the outside of the plug, I changed the ground wire from the battery to the block and made sure the ground from the battery to the fender and the body to the back of the block were tight, I'm not finding a ground from the engine block to the frame it's self. I'm out of ideas and other than replacing the unit again the manual is telling me it's the circuit or the ECM and since it's not an all the time problem I have no way of telling what the real problem is!

 

I don't know, but I would be surprised if a code 31 would feel like a "momentary fuel cut." On the other hand, an open in the FC or E1 circuit would feel exactly like that (FC holds the COR closed to keep the fuel pump running).

This suggests that you have a generalized wiring problem to the VAF, where "everything" is opening momentarily, causing the fuel cut AND the code. You probably already figured that out; that's why you checked the plug. I'd slowly work backwards from there, looking for some distress in the wiring harness. Particularly in the E1 and E2 grounds. http://personal.utulsa.edu/~nathan-b...33volumeai.pdf