Help Guys!

My '03 Stillen Stage 3 (7 PSI) has been rock solid since new. No issues. Driven only for fun, it now it has 68K Miles and is throwing 2 P0175 codes: Left and Right bank too rich. When I start the car, it idles low and rough until I warm it up a bit. Then it runs OK. It seems lower on power but I've gotten used to driving a less-tamed muscle car and cannot be sure. Only stalled once and is manageable but not quite right.

I put in the expensive Bosch Platinum plugs about 2 years ago and am about to pull them to check how they look. K&N gets cleaned fairly regularly, but not before the P0175 codes started showing up. That should not have been the problem.

What are some diagnostic things I can do to narrow down where the issue is?

Thanks guys, you are always the best source!

 

Have you looked to see what your afr's are, Or just going off of your codes? If your running rich now you may have a boost leak, has you boost levels changed at all? You dont need expensive spark plugs nkg's will work just fine. I was spitting fuel out of my exhaust and never got that code fyi.

 

I am going off the codes. I do not know how to get an AFR reading, but have the following Short and Long Term Fuel Trim readings:

B1 STFT 0.0%
B1 LTFT -7.8%
B2 STFT -25%
B2 LTFT -25%

I think that shows Bank 2 is whacked but Bank 1 also shows an error. Which side is bank 2?

 

I THINK B1 is cylinders 1,3,5 and B2 is 2,4,6.

Are you close to a dyno or a tuner?

 

The two dyno shops I go to specializes in Fords or Chevys.

Read another code. Fuel System 1 OL Fault.
Fuel System 2 CL
ECT 172 Degrees F.
Calc Load 49.0%

What does an Open Loop fault mean?
What is the difference between Fuel System 1 and 2?
Anything else relevant?

 

Is ECT 172 degrees F reading when your engine is warm?,does it get hotter than that? Your engine may not be going into closed loop due to low temp readings
Also if the ect reads a low temperature it will richen up the afr to lite up the cat converters,Whether you have cats or not...
I know my ect reads around 190F-210F roughly.
So you may either have a faulty ect sensor or a thermstat problem.

 

The ETC reading I believe is written at the time of the fault. To test that, I warmed the car up to normal temps, stopped it, then cleared the codes. When I would clear the codes with the car cold, the Check Engine light would come on within minutes. Resetting the codes with the car warm did not trip a Check Engine yet and therefore I have no entry for the ETC. I'll have to wait until it cools down to see if it trips quicklly when cold.

Another piece of the puzzle:

My on board computer says I am getting 42 MPG when the check engine light is on. Woo hoo! It returned back to normal when I reset it hot and drove it.