Here’s my problem:

At WOT when in drive, the car will shift at just 4000 rpms. When manually shifting, the car will fall flat on its face once it hits 4000 rpm and the check engine light comes on, until I shift into second gear. Once the the revs drop, the car starts accelerating hard and the check engine light turns off. That is until it hits 4000 rpms, then yet again the engine will bog down and the amber check engine light comes on, leaving me no choice but to shift into drive. For some reason the car just won’t go over 4K rpms. Did the paperclip diagnostics test with the car off and got three codes…

121 - Throttle Position sensor out of self-test range
335 - EGR Sensor voltage out-of-range
582 - Fan circuit open

I know the circuit fan is not the problem, the previous owner connected the e-fan using a single relay, did a piss poor job too, wires are all over the place, but I'll take care of that soon. Can any of the other two codes be the problem? I got a race pending against my cousin’s ’09 3.5L Dodge Charger with drop in K&N, and don’t want to lose it. :D

Thanks in advance guys. :)

i would also look at the fuel pump, i had a friend with an f-150 who had the same sorta problem where his truck was fine up to 3200 rpm, then it would just shutter, turned out to be a kink in his fuel pump hose, he did a motor swap cause he thought his motor was shot. lol

Put in a new TPS and while you're in there if you have an extra $50 or so, go ahead and put in a new IAC and I think you should be ok.

I wonder if your IMRCs are stuck closed. Kinda sounds like it as it gives a code then clears it when below the opening point.