Contour Enthusiasts Group Archives Forums General Troubleshooting Lean Bank 1/ Lean Bank 2

Hey guys what's up. Before we get started here, just want to let you all know I read through nearly every post on this topic already... and just wanted some more information/input.

Here's the deal. I have check engine light "Lean Bank 1, Lean Bank 2". Other symptoms: Intermittant hard brake pedal (suggests vacuum leak), get about 13mpgallon, runs EXTREMELY rich, when crusing about 2500 rpms in say 2nd gear... the car jerks and stutters, however when crusing at like 4500 rpms - smooth as silk, when car idles it will bounce from 500rpms to 1500 rpms and sometimes kill at stoplights.

First thought might be O2 sensors... however, it's just very unlikely they both go out at the same exact time. Also, the hard brake pedal suggests a vacuum leak which would also trip that code because unmetered air is getting in somewhere. So, the car has 75K on it - 99SVT -... so I changed out the UIM gasket - car runs a bit smoother - still same problems though. I also changed the front PCV rubber/plastic hose - which looked terrible. Even after resetting computer - light comes back on and same symptoms occur. Here are my thoughts: Perhaps it's not a vacuum leak at all, but just a faulty MAF?... would that cause these problems? Or... if it is a vacuum leak... what are good ways to test (like spraying carb cleaner on connections) for a leak? Has anyone else out there had this problem and gotten it fixed, or does anyone have any suggestions as to what to do? Thanks much, sorry for length.

I have the same thing. But my car still runs really nicely. I am gonne replace my o2 sensors, I have done everything else and the light hasn't come back, but my car is consuming an aszload of gas. So yeah, I wanna see where this post goes.

Codes ?

Change both the upper AND lower intake manifold gaskets.

You have a substantial vacuum leak. The spray fluid should help you find it.

Steve

While you're down there, clean out the UIM and LIM. You will NOT regret it. My lean codes are gone, my exhaust smells normal again, my idle is clean and smooth, and I feel a significant power gain.

I am going to change LIM gasket, MAF, and PCV hoses tonight, I will let you all know how it goes. I also noticed that I have 74K miles on my car... and while reading other posts, I have seen MANY other contours that have this exact problem at this exact mileage. I hope I find the fix for this so we can have a solid solution.