cobra intake swap help

[wolfman864]

So I have a '94 with a 5.0. I just swaped in a Mustang Cobra upper/lower intake, and a BBK 75MM. Everything bolted up good, but now I'm having trouble trying to get it to run right.

After it warms up, it likes to stay at 2,000 rpm for a couple minutes, then slowly work its way down to 800 RPM.

I was able to pull 5 KOER Codes. There are:

#8 Cylinder is lean
DTC 172-Hego (HO25) sensor fault/lean
DTC 136-Hego (HO26) sensor fault/always lean
DTC 332-insufficient EGR flow detected
DTC 411-Can't control RPM during KOER low RPM check

The engine does feel like it's running rich, but as an after thought, since I am running a cobra intake, should I change all my sensors to cobra as well?? I don't want to just throw parts and pray it works, but not sure where to go from here.

Oh ya, I did use the fiberglass spacer that goes between the upper/lower intake, but did not use a gasket between those layers, should I go back and gasket those as well??

 

[fordtech28]

Oh ya, I did use the fiberglass spacer that goes between the upper/lower intake, but did not use a gasket between those layers, should I go back and gasket those as well??[/QUOTE]

Definately need the gaskets your lettting unmetered air and that causes a lean code

 

[wolfman864]

Oh ya, I did use the fiberglass spacer that goes between the upper/lower intake, but did not use a gasket between those layers, should I go back and gasket those as well??

Definately need the gaskets your lettting unmetered air and that causes a lean code[/QUOTE]

thanks for the input, I'll slap those on this weekend then

 

[wolfman864]

Hey thanks a lot for your help guys. I gasketed the spacer on bth sides and put a new PCV and grommet and it cured the high idle issue.

In the process I fixed some codes, but picked up some new ones as well.

#8 cylinder lean
DTC 412 can't control RPM during High RPM check

DTC 314 Thermactor air system/fault during engine run self test/left side

DTC 311 Thermactor air system/fault during engine run self test

DTC 332 Insufficiant EGR air flow.

What the heck is a thermactor, and should I go ahead and replace the EGR, or is there more diagnosong I should do.

 

[fordtech28]

double check all your vacuum hoses especially the one that goes to the EGR that might be the why its throwing the code

 

[Chythar]

Jose is dead on. The four plastic hoses that lead from the passenger fender by the airbox lead to the Thermactor AIR system and the EGR. I bet you hooked the wrong hose to the intake: switch the hoses between the EGR and intake manifold. It's an easy mistake to make, I've done it myself.

 

[JJ95GTID]

Green line to EGR and Red line to manifold vacuum. You should be able to feel a dithering from the green line when engine is running.