I use to have a good shop just up the road from me that I would take the cars to when the repairs may have been beyond what i could do or didn't have the tools available to do the job. a couple of years ago i took my Bonneville over there due to a misfire problem, they said it was a bad head gasket, another shop in a different state said it was the MAF. I used the MAF out of my GP to trouble shoot the MAF issue in the Bonneville. After doing the head gasket the problem ended up being a short in the main wiring harness. Now I'll get down to my truck which is a 96 F-150 with a 5.8 in it, I had an ignition problem in the truck about 2 years ago also. I had put on new wires, plugs, distributor cap, and coil pack about 6 months before. This last week the thing would barely run, i pulled the coil wire and the electrode stayed in the wire, so that got replaced. The problem still there, so the ICM failed on the bench test, replaced it with no joy. the last part was the 2 year old distributor with less then 10k on it. When pulling the distributor I found the bolt holding it in the block was hand tight(bad QC on the shop). Once it was out the cover over the pickup coil only had one screw which was loose. The other screw was missing with tooling marks evident on the cover that there had been one in place at some time also a lot of soot from parts rubbing. Now this part that failed prematurely cost $75 and somewhere between the rebuild facility and the shop nobody noticed the missing screw. It took a dumb squid to figure that out.