Interesting Problem

[wojowojo16]

Sorry guys, I have an 01 but it is Procharged so I was thinking you could help.

NOTE: I have a wideband, at idle and cruising it stays at 14.7ish, I believe it is calibrated properly.

so I got the cobra tuned by Jon Lund in November timeframe, all was PERFECT, I mean an A/F of 11.5 across the board, etc..

Well about 2 months ago I noticed that the my A/F was dropping into the 10's then coming back up to 11.5. So, from about 3,000 - 5,500 it was dropping into the 10's, then coming back up.

I've also noticed my car stumbling just a little, sometimes around 1800rpms, drivability is fine, cruising is fine, idle is fine, etc...

I don't know what to think, any thoughts? Plugs are about 1500 miles old.

Maybe a coil acting up? Any way to test them??

could a plug not firing properly cause the rich condition? How noticeable would it be? My wideband is on the drivers bank header, so I would venture to guess it would be that side..

Thanks!!

 

[BUstang]

My car does literally the exact same thing. I'm thinking i have a small vacuum leak somewhere :/ Sorry i can't help you anymore.

 

[mysticalsnake]

here's something to think about, especially those of us with pretty severa weather changes like TX, we get fairly cold (as low as the 20's sometimes, mostly 30's and 40's though) and dry winters. makes for AWESOME tuning. However, we get hot and humid summers, and that reaks havoc with our tuning, but atleast to the safe side. getting tuned in the winter and transitioning into summer, your car will tend to richen up, and vice versa (getting tuned in summer it will tend to lean out in the winter time). Your best bet is probably to just talk to Jon about it as he very well has probably seen your exact problem before.

 

[wojowojo16]

thanks guys, and this was nothing bad about Jon, he's incredible, I just know how busy he is and wanted to run it by you guys first...

I'm thinking its part weather, part leak somewhere, just need to find out where.

 

[01cobravortech]

here's something to think about, especially those of us with pretty severa weather changes like TX, we get fairly cold (as low as the 20's sometimes, mostly 30's and 40's though) and dry winters. makes for AWESOME tuning. However, we get hot and humid summers, and that reaks havoc with our tuning, but atleast to the safe side. getting tuned in the winter and transitioning into summer, your car will tend to richen up, and vice versa (getting tuned in summer it will tend to lean out in the winter time). Your best bet is probably to just talk to Jon about it as he very well has probably seen your exact problem before.

Your dialed in tune doesn't change because the weather changes. What are you smoking?

There's something either mechanically wrong with the car or the wideband sensor is not working correctly. And of course everyone swears that their wideband sensor is top notch and infallible.

 

[wojowojo16]

Your dialed in tune doesn't change because the weather changes. What are you smoking?

There's something either mechanically wrong with the car or the wideband sensor is not working correctly. And of course everyone swears that their wideband sensor is top notch and infallible.

yeah, I'm not sure...its a pita..

I think I may have a boost leak after the MAF, that would obviously cause a "rich" condition, I'll play around for a while and see what I can find.

 

[wojowojo16]

I spoke to Jon, he said this actually happens quite a bit and my Sensor is probably acting up. He says he see's widebands properly read Stoich but read super rich or lean at WOT, which is what my car is doing.

FYI - I have an innovative Wideband.

 

[01cobravortech]

I spoke to Jon, he said this actually happens quite a bit and my Sensor is probably acting up. He says he see's widebands properly read Stoich but read super rich or lean at WOT, which is what my car is doing.

FYI - I have an innovative Wideband.

Its good he's leaning that way. Unfortunately, from what I have seen posted by tuners on this site and ModularFords, alot of these popular widebands for our cars are not high quality. Shoot, I know my tuner uses a wideband thats like over $1k. I'm suspicious of the quality of these popular widebands for the street.