Okay Here we go...... I have a 2002 F150xlt Reg. Cab 4.6 sohc 4x4 3:31 ratio in the rear, put a MAC 75mm throttlebody with spacer and under drive pullyes, cow ram air hood, going toi be adding roushe coated headers, and i have the superchips tunner for Ford Gas Trucks for it now i'm getting all kinds of DTC erorr codes with it like SYS to Lean, Misfiring, Fuel relay dvr fail, mis firing in first 1000 revs????? This is what I have done: 1. took the whole intake manifold off and cleaned it. Put it back on then retuned it replaced the IAC valv, then replaced all of the coils because the engine was running like ****!!! Then made sure all the injectors were flowing right, then looked for leaks (vacum) none the highidle is back and the same DTC's are back and the engine light is on again whast to do????????/

 

try installing oem tb-heard several stories of mac tbs causing cels and troubles

 

I hate to do this to you.... Try going to the dealer and get an opinon from a tech. It sounds like you are pretty savoy with your own engine repairs, so please excuse me if I insult you. I had the trouble code PO171 (fuel sys lean) pop up on my truck. What the service advisor said was it's because I changed my MAF sensor. I reinstalled the original MAF sensor and my check engine light cleared (for now). Good luck...

 

Guys you are great for even answering me so you are not insulting me by nomeans, There's no such thing as a stupid question and there's always room to learn som ething new!!! So it's cool if i knew it all i wouldn't be asking you guys for help. You guys are cool in my book, so anyway to answer my question, i was told by the speed shop who i have delt with for years is that i called superchips and they said that the throttlebody wasn't compatible with their tunner, So i went back to the speed shop and he said that the tech was off his rocker. So the guy at the speed shop has told me that he's been in the horse power game for 30 years. So i don't know who to believe so that's why i'm here.

 

30 years ago, the horsepower game was all about cams, carbs, headers, compression and timing... Not about PCM's, IAT's, IAC's,throttle bodies, computer fuel injection tuning, MAFS, etc.
Listen to the tuner manufacturer or get a custom tune.

 

i will do that and i'll get back to yiou guys as soon as i get the real deal and tell you all what the deal is word for word ok