Engine shakes and pings, installed new plugs,fuel filter, and MAF sensor due to high elevation readings on baro, no change. Fuel trim double on left side compared to right, baro now at 28.3 HG No dtc's, O2 readings OK timing advanced cust states he hooked up jumper cables backwards recently, wondering if he fried the CPU? Any help appreciated!

 

This sounds a little worrisome. I would start at the very basics and do a really quick (one clyinder on each side) compression test (it's all those years of driveability). You should have compressions of somewhere around 150 + depending on elevation; I'm in Denver, and the readings are a little lower). If thats OK (I'll bet it's not), then, could you give a Baro reading in Hz? Usually, but certainly not always, when you have a lot of symptoms (especially when O2 split is like 30% off), it's a timing issue. Sometimes, cams will spin/break, sometimes they're mistimed by someone. Fords are very touchy about jumping wrong, and that's a good guess after verifing timing. If you look at pids, try looking at spark advance. Sometimes when pcms fry, the computed advance will not change. It should.

 

Thanks I am going to perform a comp test and fuel pressure test today, Here are some of the readings Baro 28.6hg, calc load 23%, rpm 865, LT FTRM 1 25% LT FTRM 2 -4%, MAF G/S 1178, ST FTRM 1 -9.4% ST FTRM 2 23.4% I was thinking the same thing about Fords jumping time on one side (chain) vehicle has 99K on it and it is a work van. Any more input will be helpful, I have to get the adapter for the comp gauge for the deep plugs, so much fun!! And of course it's the next door neighbors van! Some of the baro conversions are 28.6 Hg=969mb or 726.8mmHg if that helps.

 

It's about all screwed up. The o2's read lean when there is a miss (it reads oxygen), so start w/bank 1. If the compression is low, take apart the front of the engine and find out why.