88 Bronco 2, low vacuum, runs rich.

[ghostman916]

I have a 1988 Bronco 2 4x4 2.9 v-6 95,xxx miles. Bottom end redone last year(rings, bearings, cam lifters and a valve job.), the motors runs really rough. Vacuum test showed 3 pounds. Pulled power brake booster line off with engine running and it didnt die. Feul pressure test shows 40 psi BUT falls to 0 after the high pressure pump stops running. No injectors are leaking. Any info or sugestions would be helpful. I pulled the upper and lower intakes off just to check gaskets, no leaks. But I did find a discoloring and bubbling effect between cylinders 2 & 3. These are the cylinders that wont fire or mis fire. Spark and fuel are there. Compression test showed 120 psi.

[shelbybronco]

Check on the back side of the engine(I believe on the passenger side) for a ground wire. I believe it is the ground for the computer. It should go to one of the bellhousing bolts. I only know this after buying an 89 bronco 2. It would run very rich and had no power. I replaced all of the sensors and tried tons of things none of which worked. I only found it after the flexplate broke. I was reaching back to unbolt the bellhousing and found the wire. Someone had replaced the engine and forgot about the wire. I grounded it and it ran perfect after that. Hopefully it will help you