Another Check Engine light Problem. Help

[kenaroo]

Have an 01 SVT 4.6 engine with K&N and Borla exaust. mods were done when new. Car as 8K miles

Check engine light has been going on for the last 4 months. Dealer can't figure it out.

they change out parts and reset light.
After fill-up and/or after about 50 miles light comes back on.

they are baffled and I just want the light off.

So here is what it's doing


Showing Codes: PO172 and PO175 Car is rich. Has also showed PO171 - po174 in the past

List of parts dealer has change out:
F6UZ-12B579 SENSOR ASY-ENG
YR3Z-12A650-JA PROCESSOR ASSEMBLY
F8ZZ-9C915-CA VLV ASY-FUEL V
F50Z-9601-BA ELEM ASY-ENG A
F8CZ-9F972-BE SNS ASY-FU/INJ
F57Z-12A697-A SENSOR ASY-AIR
2C6Z-12029-AA CIL & BT ASY-I
SPARK PLUGS
XR3Z-9F593-CB INJECTOR ASY-F
XR3Z-96444-AA SENSOR ASY-EXH
(all parts warrantied)

Also Know they change out rear O2 sensors the first time I brought car in.

If you tech guys can help me figure this thing out, that would be great.

If you need more info let me know

thanks:
Ken

[Milw96Cobra]

Sounds like your MAF might be improperly tuned... you may want to take your car to a dyno... well, for a couple reasons..
1) To see the actual mixture of Air/Fuel
2) Well, for fun, see how much power you're puttin down

If you actually are running rich, you have a few options.

1) Get a MAF Tuner, and cut back the fuel.
2) Get a new computer stock computer for it
3) put a superchip on it to manage the fuel.

[BlueOvalBolt]

***WARNING***DANGER*** I am not a Ford Tech but FWIW:

IF it is a fouled MAF, could you have applied too much oil on your K&N filter when and if you cleaned it?

I always thought when your Check Engine light came on it meant you had something wrong with your emission system. The O2 sensors and the like would have been my first guess too.

(BTW, what dealership are you seeing for this?)

Any ideas from our resident Master Mechanics, Curt/Marv?

[Milw96Cobra]

Originally posted by BlueOvalBolt
***WARNING***DANGER*** I am not a Ford Tech but FWIW:

IF it is a fouled MAF, could you have applied too much oil on your K&N filter when and if you cleaned it?

I always thought when your Check Engine light came on it meant you had something wrong with your emission system. The O2 sensors and the like would have been my first guess too.

(BTW, what dealership are you seeing for this?)

Any ideas from our resident Master Mechanics, Curt/Marv?

Good call, I hadn't even thought of that. That could very well be it too.

[BlueOvalBolt]

Originally posted by Milw96Cobra
Good call, I hadn't even thought of that. That could very well be it too.

Well, thanks, but my leading theory is still that his Cobra didn't get his prescribed dose of Magic Blue Oval Dust at the factory. :D

[Yellow Iron]

It sounds like a MAF problem, possible contamination from excess oil. I would be glad to look at for you. I'll get it fixed. I can do it under base warranty if it's still covered. Give me a call 262 628 9974 or send me a email. Marv Z

[kenaroo]

Thanks for the input guys, I'll check the filter and go from there.

Would love to bring it to you Marv Z, I'm a little far from Wisconsin these days. I'm from Brookfield (133rd and Capital Drive) but living down here in Austin TX at the moment.

Knew you guys had a good bb for SVTs. That's why I posted here.

If you know where I can get some more Majic Blue oval dust, PM me. Seems my '01 supercrew "king ranch" got it all. No problems with 28k. You got to have a truck when you live in Texas.

Will keep you guys updated with my results.

Ken

[CSCOBRA]

Your check engine light could well be a MAF . A good Ford service tech should be able to figure it out.:bash:

[kenaroo]

So...

I started thinking about all that they did to it. It had to be something they overlooked. Hell, they replace every processor etc. on the car.

Read somewhere that a CEL could come on with a bad gas cap.

I remembered droping the cap a right before all this happened.

Asked the dealer if they check the cap. Pretty much told me that if that was it the SVT tech would have caught it. In other words, no.

just to check my theory went and bought a new gas cap. and reset the light.

Tada! no more check engine light for over 300 miles.

Sometimes it's just the little things.

Man am I happy that that things off.

Perfect for 70+ degree weekend. drove around with the top down the whole time.

LOL

ken

[Yellow Iron]

Sorry to be a downer, but there is no way a Evap system failure (loose fuel cap)will set a P0171/174, PO172/175 code. Thats fuel lean/rich on both banks and is not related to the fuel cap. Resetting the light will make the PCM go through a drive cycle before it turns on the MIL. Depending how you drive that can be from 1 day to a couple weeks. But it will be back!!! If it comes on again, have a dealer pull the codes and get a copy of the freeze frame data. That will give me a idea of whats going on. Let me know if Ican be of any help. Thanks!!! Marv Z

[xbnch]

Just was reading all this stuff about problems after doing mods. I was planning on putting Magnaflow exhaust system on but should I expect sensor problems?
Help? :confused:

[kenaroo]

Marv:

unfortunately you were right. Light came on this morning when the wife was going to work.

I'll pull the codes and send it to you this week.

Ken

[Yellow Iron]

Regarding installing a magna-flow system, you will not have a problem with a cat back system or a X-pipe with cats as long as you use the stock manifolds. Going to long tubes involves relocating the O2's and that can be a problem. Going with an off road pipe is almost certain to give problems even with MIL eliminators. My advice is X-pipe with cats off stock manifolds and cat back from there. Marv Z