I would be looking harder at O2 sensors, or coolant temp sensors.......

 

Thanks for the response! I will keep looking to the O2 sesnors. There are only two o2 sensors on the 5.2 liter correct? I have replaced the upstream one (autozone part so it is possible that it is faulty) and have the downstream one set up on Non-foulers because My cat is bad and I have not replaced it yet. It was set up this way when it was getting 14-16 MPG and it is hard for me to believe that it was a cooincidence that as soon as I put the intake on I began having this problem. I have not looked into the coolent temp sensor, that was the next item on the list if the MAP sensor didn't take care of it.

I had the CEL code checked and got P0171. It indicated MAF sensor (these trucks dont have one) vaccume leak (checked with carb cleaner and found None) or 02 sensor.

 

to answer the oil consumption question. I replaced the plenum and cleaned the TB a few months ago so I've not been burning a drop. I leak a little out the rear main seal but less than 1/4 of a quart in 3K miles.

 

The charts here say P0171 is "system running lean." Points even more toward a faulty (or, cheap.....) O2 sensor. These trucks seem to HATE aftermarket sensors....... and even a brand new one right out of the box has caused trouble....... Folks have had good success with the NTK?? brand O2 sensors, or, the one ya get from the dealer...... Might wanna give that a shot, and see what happens.

May also be low fuel pressure........ Wanna check that first methinks.

 

change the coolant sensor, and ALSO your temp gauge sensor, which on my 94 318 it's right behind the altinator, hard to see, I had those sputtering problems that my truck couldn't go past 20mph, I replaced alot of sensors, but when I changed the temperature gauge/light sensor,
My truck has excellant idle, and more power, NO sputtering at all.