IAC is a four pin connector. With the ignition on, and IAC unplugged, you should see power on two pins. It varies which two pins though..... there are two circuits thru the IAC, and the pcm will apply power on both, pretty much all the time. It tries to send them in opposite directions to lock it in place.

 

1 pin has power so should I test at the Pcm for signal and check wiring.

 

Yep. Wouldn't be the first time the drivers in the PCM failed.

 

Ok it doesn't have power on the wires right out of pcm either. Do pcm s interchange? Would junkyard be best bet?

 

For a 94, you just need a PCM for the same size engine, and correct transmission. Anything from 94-95 should work.

 

Cylinders 7 4 8 have no spark. Not at plug and not at cap. How is this possible? New cap and rotor and new wires. Good spark out of coil to.

 

I have weak fuel pressure. But new cap fixed spark problem. Told them the new cap wouldn't work and they replaced it.

 

I was told my truck had a tune up but when I looked , they didn't touch the cap and rotor either . Not surprised about the fuel pressure .

Glad you're making headway

 

Found a round piece like a secondary fuel pump on the frame in front of the tank. Thought mine was internal? It had fuel lines on it it looked like.

 

Probably part of the vapor recovery system. Fair sized plastic tank?