Running Lean-need help

[pendelton]

Ive been having nothing but troubles with my SHO for the past month-just cant get her to run right. I NEED Help! First the thermostat was stuck open making the plugs foul from running rich. I replaced plugs and thermostat and the car ran great for about 2 days. Now i beleive im running lean cause at start up for the first minute of driving the car responds as it should. I do have a MAP sensor code on KOEO test(which i replaced to no avail)
BTW i did purchase a pro-m 75 mm, Which did not help(or hinder) the situation. My last attempt at fixing this is replacing my y-pipe with a recently ordered SHO Shop one cause one of my cats is possibly clogged, but still if it were clogged it wouldnt respond so well at start-up. I dont know, Im outta ideas. Any suggestions are much appreciated!

 

[93nighthawk]

What are the codes you are getting (please list all of them)?

Did you pull the intake off when you replaced the plugs. If so you might have not sealed it correctly and unmetered air is getting in causing your lean condition, which would also throw a MAF code. I had the same problem, and it was fixed by taking the intake off, cleaning the mounting surfaces with B-12 and re-sealing it.

 

[pendelton]

only code 126 (MAP sensor) I did not pull the intake though

 

[projectSHO89]

Unplug the MAP/BARO sensor and run without it for diagnostic purposes. You will get a CEL, but the computer will compensate for the lack of sensor input by substituting default values.

See if running without the sensor changes your symptoms.

Steve

 

[93nighthawk]

Did you do a KOER? Engine balance test? So how do you know you are running lean with only a code 126?

...The only other thing i can think of is if one or both my cats are clogged, today i found a piece of catalyst coming out the hole of my muffler....

You have your power loss problem, and get those cats off before you destroy your engine. You don't have your SS cats yet?

SHO's do not use a MAP sensor, I missread that, they use a Baro Sensor. Here is a link and pic!

 

[pendelton]

KOER gives me nothing but 126 code-all cylinders are running fine according to balance test. All Plugs look fine. Im Guessing its running lean, if it was running rich i know it would show by carbon deposit on the plugs. Fuel pump has proper voltage and i tested it today and its putting out enough pressure. Once i did take off my whole exhaust to see if open headers would help it run better but it didnt-could that be because there was no backpressure? Well still waitin on cats, hopefully they will be here soon!