I just finished installing a new APN manifold on my 1995 Country. The base of the stock manifold was cracked around the collector and had a temporary epoxy fix for the last three months. The Jeep ran fine and had no issues aside from an occasional misfire while idling and gas mileage in the 15mpg range.
I finished the install earlier this week. The exhaust note seems a little deeper but not excessively loud (although the cabin is a bit loud at highway speed as I removed all the sound deadening/water collection material from under the carpet). The misfire is gone and the mileage seems to have improved although I have only run through half a tank since completion. The only issue I have is a random check engine light that comes on and goes off. This was not on prior to changing the manifold. The key check method gave me 12, 51, 55 which I read as battery disconnected, o2 sensor reads lean and end of codes.
The previous owner replaced the exhaust from the cat back, not sure what brand or type, but it sounds good and passed emissions with no problem. I read the 1995 has two O2 sensors, one just after the manifold and one after the cat. I found the one after the manifold, but cannot find a second sensor. Any ideas if this needs a second O2 sensor and if this might be causing the code 51 issue?

 

95 had one o2. Try unhooking the bat, then shorting the neg and positive together, while battery unhooked, will reset comp. I had the same problam after exhahust work. The long term fuel trim was off cause I had leakes.

 

Would leaving the battery disconnected two weeks do the same thing? This drains any residual charges in capacitors in the system?
I tried this reset procedure today and will see how things go over the next week or so...

 

Not sure on the two week thing, I would assume that would work also, but maybe not.

 

That was how long I had the battery disconnected while working on the exhaust, interior and other projects. Unfortunately, no joy on the reset. I guess I will be figuring out how to test the MAP sensor and maybe replace the O2 sensor?