Truck stuttering after taking off k&n cai.

My truck has been stuttering at low rpms when I was driving after I put on my cold air intake but I took it off and put my old one back on and it's still doing it. I'm thinking it could be my MAF sensor but I don't know. Any help would be appreciated.

 

Throw the K&N in the trash where it belongs, replace the stock intake, and buy some MAF cleaner. Clean it throughly, down inside the tube. Uou should probably pull the intake hose off the throttle body and spray that out too. Make sure the butterfly is rotating freely and not stuck closed.

 

Did you check for vacuum leaks?

 

Yep, I ruled out everything but the throttle body I sprayed some cleaner in he throttle body and maf sensor and it keeps doing it.

 

Did you disconnect your battery to force the ecu to relearn?

 

Yep I did

 

Ensure that the harness is snug on the o2 sensor.

 

I did, they were tight

 

Did you put back on the OEM air box?
Or the old CAI?

 

OEM

 

^That vacuum hose from the fuel rail is connected to the nipple on the back of the OEM air box and the hose is in good condition?

Make sure the OEM air box is clean (the convoluted shape likes to trap debris) and the wire screen upstream of the MAF sensor is clean.

 

IICR the MAP sensor has an arrow on it on which way its suppose to point. Make sure you have it correctly.

Inspect the hoses attach for any leaks...spray some soapy water for air bubbles.

 

Nothing wrong with K&N filters (or really any oiled filters for that matter) if you know how to oil them properly.

That said, if you didn't have the issue before you installed the new intake, then something either broke or was installed incorrectly during the installation process. Leaning towards something breaking if the behavior stays after reverting back to stock. Sounds like it could be vacuum-related or a sensor somewhere got disconnected.

Did you unhook the negative terminal on the battery during the install so the truck can learn the new intake value (and when you reverted)?
Any CEL's from the install?
Did everything get hooked back up 100% stock when you reverted?
Airbox, MAF, intake tubes and any vacuum lines in good shape with no cracks or splits?
Did you disconnect anything else during the install process that you might have overlooked when reconnecting things?

 

Yes I unhooked it both times, no check engine lights, everything is replaced back as it was, the lines look brand new, and no I didn't. The only new thing I can find out is that I goes into limp mode when I put too much throttle on it, and the codes were for a misfire and a o2 sensor but the o2 sensor looks fine. The CEL went away as soon as I turn off and on the ignition.

 

Misfire would definitely cause an issue you would feel. If you can grab that code again it should tell you which cylinder had the issue. O2's don't go bad that often and if it was a generic 0300 code it might just be a general fault, and something was temporarily pissed. Hopefully you get it all sorted out soon.

 

I think it was cylinder 4 if I remember right. Thank you btw. I appreciate you

 

With a misfire a quick option to check if it's the coil or the plug is to swap the ignition coil with another cylinder and see if the issue 1) comes back and 2) stays in the same cylinder or moves.

If the plugs are old though, sounds like a good time to swap em out.

 

If you only cleaned the front of your throttle body, you should take it off and clean the backside as well...

 

The 4.0 doesn't have a MAP sensor.
You mean the MAF sensor?

 

The MAF sensor screw pattern isn't symmetric, can't install it backwards.