New here. Time for some brain picking.

[Boltslinger]

2000 Expy 5.4 2v. Just rebuilt engine and trans. Basically everything is new, inside and out.
Only non stick item is 20+ pistons.
Having a real performance issue, and electrical issue. Maybe related? Been through all the wiring, ohms and VD.
Chasing a random miss. Just jumps around to different cylinders. Not enough to throw a code, but I can see it on the scanner graph. All cylinders are at 220psi even. Maybe I should run a higher octane with that comp? Am I chasing pre detonation?
Electrical issue: At idle, blower speed goes way down and I have far less hp with ac on. My ac isn't really cooling like it should. Ac compressor doesn't seem like its binding spinning it by hand with clutch engauged.
Any thoughts?

 

[bear1butt1]

Check computer

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[stamp11127]

Look at the fuel trim to see if it is running too lean but within range. If so then may have a vacuum leak.

 

[Boltslinger]

Been through all that. That is what it's been seeming like though. Even replaced the intake manifold and smoke tested the entire system. Vacuume is 17 steady.
Fuel trims have been at Lt-0 on both mainly. Though today RB was at 2, LB -1.
New upstream o2 cause one was lagging bad.

 

[Boltslinger]

Update;
Finally figured out what the problem was. Turned out to be intermittent torque converter shutter caused by a cracked intermediate cylinder in the trans. Of all the bs...lol

 

[1955moose]

Well that's one for the books. Got to remember that one. How'd you figure it was in the tranny? And why would that make the cylinder jump around? These SUVs never ceases to amaze me as to their quirks.

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