Hey everyone, so I’ve run into a problemo with my 1994 3.0 2WD auto Ranger. I believe Its been running very lean, Heres a photo of one of my spark plugs below all 6 have about 7-10K miles on them. And they were all the same white color. I’ve ran codes with a cheap eec-iv scanner and have gotten several different codes i’ll list a few from last time I ran a KOEO and KEOR tests

113 Intake air charge temp sensor above max voltage / -40° indicated

335 EGR sensor circuit voltage higher or lower than expected duribg self test

10 ?

157 MAF sensor fault low voltage

327 EGR valve position circuit below min voltage.

332 Insufficient EGR flow detected

I’ve had more codes but I don’t have them all written down.

Its been throwing so many codes I am absolutely clueless as to what it could be at this point. Surely not all of those faults are independent of eachother, most likely just one sensor/part has gone bad and is fouling the rest right? Any help or recommendations for figuring this out would Be GREATLY appreciated

And a few other details I checked my o2 sensors and it seems that only one has been replaced. Also I believe my TPS, IAC and MAF have been replaced before I got the truck. And I replaced the EGR position sensor last year along with a new fuel pump+fuel filter.

& when accelerating cold the engine seems to rev up and down not an insane fluctuation in rpms but just enough where you can feel the loss of power. I believe that to be a symptom of it running lean right?

Sorry for the overload of info but heres the last thing one of the drivers side spark plugs closest to the cab had its spark insulator cracked (the white part on the spark end of the plug) had a big piece of rubber debris on top of it in the plug well, I believe it cracking was unrelated to the lean condition because of the debris on top of it causing it to overheat. Btw truck was skipping and shaking before I changed that plug out. Its back to its old lean self.

Thanks for anyone who read all of that your the best!

BTW I’m 99% certain I do not have a vacuum leak anywhere.

 

Lean running causes pinging/knocking, you don't report that?

3.0l Vulcan is known for pinging/knocking, so its not subtle, lol

Code 113 would cause Richer running

Other codes are EGR related which can cause pinging/knocking if its not working during acceleration, warm engine

Make sure the connectors on distributor and TFI module are clean and tight, spark advance issue can cause the RPM changes you describe

 

Thanks for replying! I haven’t noticed any tapping/pinging/knocking before you mentioned it, but its very quiet. More like a lifter tick to me. not as auidable as it sounds on video. (I tried to attach a video idk if will go through) Also where is the TFI module located? Also the rpm fluctuation happens when truck is cold and won’t go away until its warmed up to op temperature. Then it will run & accelerate better but will occasionally still fluctuate. This trucks issues are mystery after mystery for me 😤 Lol

 

TFI module on the 1991-1994 3.0l would be on the rad support, near radiator

Swap out your IAT(intake air temp) sensor, code 113, that may get surging to stop as well

 

Alright I’ll see what I can do, Thank you for your help brother!