05 4.0L Throttle Pulsing around 2500 RPM

My buddy has a 2005 Taco with a 4.0 L. Trying to fix it up so that he can sell it.

Has CEL on, and it read out at Bank 1 and Bank 2 System Lean (O'Rielly's scanned it last night and thats all they would tell me). This is from his CAT delete that he did years ago. This problem started well after that.

When driving, the throttle will pulse around 2250 to 2750 RPM. It runs fine up to and past that point. Have read that it may be the fuel pump resistor assembly ?

Has anyone had this problem before ? I'll try to attach a video showing it.

 

Alright so i just talked to my buddy. He said that it was doing this before he put the headers on and before the CEL came on. Any ideas ?

 

What was the MIL Code Number? ( PXXXX )

 

Cat delete does not cause banks to be lean, cat delete code will be cat effiency as the computer will see the cats aren't doing there job. Sounds like some sort of vacuum leak this could cause hunting at that rpm and lean codes.

 

Well it turned out to be the fuel resistor that sits in front of the battery in the engine bay. It ohmed out at 2.6 ohms. Took a wire and jumped the connector and problem did not continue. Awesome !

 

Awesome pass it on.