Hey guys, I've been having some issues with my truck ever since I replaced my head gaskets back in August. 93 dak 5.2L RWD automatic.

The truck idles rough when warm, at about 200 rpm's - changed IAC in September, noticed a slight improvement.

When I turned on my headlights, the tachometer jumped wildly. I resoldered my alternator ground and it seemed to fix the problem. Also have a new PCM and a 7 month old alternator. Alternator now tests good at 14v at Advance.

The truck cuts off on the interstate driving at about 65 mph, just dies. The other day, it acted like it was about to cut off while driving at 55 mph, but I gave it some gas and it was ok. Another time, my truck cut off when I turned on my heat. Haven't used the heat since. Before the truck gives any signs of cutting off, it sounds like it's operating normally 45mph+.

I resoldered all of my notorious splices back in August.

These days, after the truck has warmed up, when I let off the gas pedal the rpm's drop to 200. So low that I can't hear my truck at all. I'll usually stomp on my brake to get the truck to downshift, rev up some and not cut off.

Took my truck to the mechanic, and they said the fuel pressure's good, and will start investigating electrical. Is there anything I can tell them to point them in the right direction and get me driving again?

I'm too busy to fix the truck myself, unfortunately. Thanks in advance for the help!

 

Have you tried replacing the O2 sensor?

 

Cat (and that O2 sensor) was removed by PO, replaced with a straight pipe.

Are there more O2 sensors in the engine? I replaced a sensor on the top front passenger side of my intake manifold, pretty sure that was an O2.

 

O2 Sensor would be located right before the cat on the exhaust, on the passenger side. You replaced the IAT sensor. You need that O2 sensor in order for the engine to run right.