PCM Fail on reader

[96RangerRed]

Hi guys, ive been slowly rebuilding my 96 Ford Ranger 4.0L OHV and the last thing is exhaust. however a new fault popped up on my OBDII reader and it says "PCM Fail" not sure what happened but it just showed up a few days ago. now a bit of information for you here, I have Installed a slightly bigger camshaft (not oversized) its got a cold air intake, dual valve springs, and a BBK 62mm Throttle body on refurbished engine with about 3,200 miles on it. it has no exhaust system really so no O2 Sensors and im not sure if that's causing my issue or not but have a massive power loss and bad fuel mileage (for a Ranger). also my blinkers stopped working after I put LED Headlights in... and every once in blue moon my check gauge light flashes once and does not come back on and i get the same codes on my reader for O2 sensors and the PCM fail. also my throttle gets stuck open for a while when I shift gears, I have to pull the pedal back with my toe.( and yes I have cleaned my throttle body several times and no change I also made sure all my vaccum lines were attatched correctly.) thank you!

 

[RonD]

Throttle is not sticking, RPMs are suppose to stay high between shifts and only drop down after 5-8 seconds.
This is done by the IAC Valve and computer.

But to be sure check throttle movement, engine off, at the throttle linkage, make sure spring snaps throttle closed.

Without exhaust system there is no Scavenged power, so you will have a power loss

And without O2 sensor feedback computer has to run the engine Rich(low MPG) to avoid engine damage, Lean WILL melt pistons and valves

"PCM Fail" usually means no communication with computer from OBD plug in port
Engine could not run with failed PCM(computer)

Check if you have power at cigarette lighter, that fuse also powers OBD port

 

[96RangerRed]

ok thanks, however my throttle has never done this in the past when i said its sticking what I ment to say was its jumping to 3500-4000 rpm when I let off gas and push in my clutch, now when it settles its at the normal 1200-1300 range until I make a complete stop then it returns to idle at 830-890 rpm. These readings come from watching the live data on my reader.

Edit: the Throttle springs back just fine to I just checked that and its fine at 17 degrees and a cold engine.

 

[Dirtman]

I got 20 bucks that says if you put the stock intake, throttle body and exhaust on it will make more power, get better mileage, and stop throwing codes...