New to the site, did a search couldn't quite find my problem though.
I was leaving work the other day and as I was going down the road, my check engine light popped on and the truck shuddered and lost a lot of power. It's a 91 lariat and I've already replaced the fuel filter and ignition igniter module. If the truck is cranked and running it does fine, but after a while 5 min or so the check engine light will come on and it runs terrible. I can't give it full throttle without it bogging down, it acts like it doesn't shift, like it's stuck in drive, and if it goes dead I have to wait until something cools down before it will start and it's fine again for a few minutes. I had Oreileys do a check engine test and he told me that he can't get a reading because the test point has no power. I'm racking my brain on this please help.

 

Oreilly's and Autozone don't normally do that for an OBD-I vehicle...If there's no power at the connection point, check your fuses. If those are good, it may just be a bad computer. I'm coming around on wiring, but computers are way out of my league. Maybe somebody else can chime in...