93 4.0 code 512 rough running
 

Any help would be much appreciated. Just got the truck and cel is on. Underpowered and surges while driving till throttle is depressed 3/4 or more and it clears up and runs strong. Checking codes manually I got 111and 512. Light went out for a night not sure why or how, but it ran a million times better. Light came back on next day and right back to being sluggish and feeling like its cutting out while driving. Tried clearning codes using the jumper wire, pulling pcm fuse, and disconnecting battery. No luck getting the code to go away

Welcome to the forum

111 System checks OK
512 Memory power (PCM pin 1) was interrupted or battery disconnected <<<< you did this

so neither would cause engine issues

On the4.0l
Clean the MAF sensor
Unplug TPS(throttle position sensor), this should turn on CEL full time, drive truck to see if it runs better without TPS
Also check codes again to make sure TPS code was set

Ford 3 digit codes found here: https://therangerstation.com/tech_li...gitcodes.shtml

With a 1993 you can read codes using CEL to flash the numbers

Juust changed out TPS light was on when I got the truck so I did not set the 512 code off. Only code I've gotten besides the 111 check ok. IAC valve is on its way as well. It lacks power mainly at highway speed is when you notice it almost shuddering like fuel is cutting out.

I will clean the MAF too but wondering what else it could be. Most sensors look to be original

Sensors rarely fail but are often replaced, lol

I think the number is like 50% of DIYers replacements were un-needed, and 20% of pro-mechanic replacements, but I think the later is bill padding

Best practice is to unplug any sensor or control, and plug it back in, most sensors use 5 volts, so a poor connection effects the voltage, simply unplugging and plugging back in cleans the contacts, which is often why installing a new sensor can work, but a waste of money when you just need to clean the contacts

O2 sensors do run out of chemicals, like batteries, so should be replaced every 100k miles or so

TPS needs to be replaced with a Motorcraft or Hitachi brand, other brands won't work well on Fords

There is no sensor for "power", so can't answer that question
Computer calculates air:fuel mix for best power based on RPM, MAF sensor, TPS, and O2 sensor