Engine 4.6 Running rough at half throttle

[jake411]

Good after noon all, I have an issue with my 96 sn95 that i have not been able to figure out.

First ill start with all of the mods that are done on the vehicle
-accufab throttlebody and plenum
-Ford Performance Intake Manifold
-NPI block with PI heads
-BBK catless h-pipe
-Borla Catback
-Cold Air Intake

But ever since i have owned the car, 4 years now, i have never run it with a MAF because it has always run rough.
Well after doing a pi head swap i figured id try and get it running properly with the maf.

Well, i plugged in the maf and with the MAF plugged in it only runs good at anything under 1/8th throttle, or full throttle. Anything inbetween it runs so poorly it sounds like its two-stepping, It also smells like gasoline out the exhaust.

I ended up replacing the maf to find the same results. I got my scanner and watched live data and The MAF data, AndTPS sensor were at the correct value.

ill send a video of what it looks like. my thought is maybe its not calculating the MAP right and its throwing too much fuel at the issue? i dont know i am stumped. any inputs or ideas will help.

 

[squeak93]

The maf is absolutely required unless you've tuned aftermarket for speed density. So you put a new one in and it didn't improve? I would start checking wiring etc. Also, is the iat sensor picking up correct temps? What cold air - metal pipe with provisions for iat or a plastic jlt type etc.

Next up -how are you tuning around the cel for the no cats and newfound air intake etc?

 

[jake411]

I have gone through the wiring, ill go through a second time to see if i missed anything. And yes i have replaced the MAF to no avail. I am running an unknown brand aluminum CAI, with iat sensor past the maf. and the iat is reading the correct temperature. and to get around the cel for the no cats, i am running a SCT tuner and have the rear cats disabled, but i do not have a custom tune for the rest of my aftermarket parts.

 

[squeak93]

It should run fine on the stock tune- not optimized obviously but fine. Short of an ECM issue - I'd look at all your grounds and connections again just to make sure.

 

[jake411]

Alright, ill take a look and go through the harness again and verify grounds. Ill keep this forum posted, thank you!