Running issues

[1989DropTop]

Well I got my vert of the garage for the first time in 3 months. I drove it down the street after warm up and found the car was missing. It would come alive if I put my foot into it. The car would shift in to overdrive and start running doggy as hell foot into it runs awsome. at idle has mild miss here and there but not too noticable. the most noticable is under load. I ran codes and get the basic crap for oxy sensors and idle high and out of range which is bs. The car is idling at 1000 rpm tops. The car is stock currently 5.0 automatic with 85,000 miles on it. New cap rotor plugs wires headers new oxy sensors, dumped codes and still get check engine light. Unplugged the light. so asking for some advice here on what the heck it could be. I am building a motor for it this winter but would like to take it out once and a while in the mean time. Brian

 

[Mustang5L5]

1000 rpm is high. You should perform the idle reset procedure and bring it down to proper range.

O2 sensor codes are important, you'll want to address those.

If your check engine light is on, you have a major code stored. Did you run the codes with the engine running as well?

 

[1989DropTop]

1000 rpm is high. You should perform the idle reset procedure and bring it down to proper range.

O2 sensor codes are important, you'll want to address those.

If your check engine light is on, you have a major code stored. Did you run the codes with the engine running as well?

Hey Mike Yes I ran with running and only code I get is rpm out of range running, not running I get o2 sensors but they are brand new 3 miles on them. I will look up the procedure for idle adjustment and reset dump the codes again. The engine light would go off and on as I drove the carat idle it was on at any type of rpm no engine light. Thanks for input. Brian

 

[Mustang5L5]

Do you have the code numbers you got?

I have a few suggestions but need to know the specific o2 codes you got.

 

[1989DropTop]

12, 41, 91 are the only codes i am getting

 

[Mustang5L5]

Those were the codes I was guessing you had.

So new o2s then? If so, usually double lean codes indicate an issue with something in the engine being out of tune. Could be a vacuum leak, dirty MAF sensor, egr valve stuck open, etc.

Is your smog system functional, do you have any smog codes?

Most of what I'm about to recommend is covered in this thread.

http://www.stangnet.com/mustang-forums/762521-code-41-91-a.html

 

[1989DropTop]

Thanks Mike I will read through it. I have all smog equipment and as far as I know all is fun****ional. Brian

 

[1989DropTop]

Hey Mike, I found nothing that would cause this after working on it for two weeks I found the bottom of the stock air box was not fastened properly letting air from the fan disrupt the air flow to the mas air flow sensor. Re sucured the air box and the thing runs like it should!!! Brian