“Ghost in the Machine” - 93 severely loses power
My 93 L67, has been severely losing power intermittently. It started a few months ago occurring once a week. Now its up to 4 days a week.
When it acts up, it feels like it is going into limp mode. It takes a very long time to get to 60 mph and sometimes I can barely go more than 25 mph
It doesn’t do any better if I downshift. If I floor it in neutral it howls and will not go over a certain rpm (1500~3000 rpm depending on its mood)
On its better days it has good power except it stumbles and bucks a little at WOT (this may be a separate unrelated problem)
It does not throw any codes.
Tranny seems to be shifting OK. Always runs smooth like all cylinders are firing.
Does not make a difference if its hot or cold or raining – occurrence is pretty random. Sometimes it will do this on first start in the morning in open loop and power decreases as it gets warmer.
Work done so far:
Swapped PCM, ICM, and coils with known good ones and it made no difference. (did not have a mem-cal to swap though)
New O2 sensor, TPS checked and adjusted, EGR cleaned and solenoids checked. Plugs and wires have about 8~10k miles.
Last fall it got new fuel pump, filter, FPR, and newer injectors from another member. MAF sort of cleaned (best I could do without removing it)
I have been running without a Cat lately. (my exhaust is flanged so its very easy to swap over to a test pipe.) When I run with the cat, it still has same symptoms on its bad days.
By its randomness and having some good days, I think its most likely electrical.
Dont know what item to tackle next. Any suggestions?