I might be a little premature writing this as I have not tested the fix for more then 30 minutes of driving but I wanted to get the details down
My truck lost power going up a hill 5 hours into a 8 hour drive last week. I pulled off onto a secondary road and it began studdering and barely able to drive 20mph on a flat road. It was a 100 degrees that day so my trouble shooting was not a strong game. The truck could idle smoothly, but would pop, sputter and even backfire when reved up by hand. I thought I had lost another fuel pump since the symptoms were similar under throttle. It finally gave a P0125 code, but in that last troubleshooting effort I re-seated the maf connector(and tapped on the maf), checked a coil for oil down on the spark plug and disconnected the upstream O2 sensor for the P0125 code. The truck then ran but was significantly down on power. It felt like it was missing a 3rd of the horsepower.
I figured this power loss was due to running without the fuel tuning provided by the O2 sensor, but a new sensor did not fix it.
I thought then that I had melted the cat while the fuel ratios were off and plugged my exhaust, but a local guy showed my the inlet and outlet temp of the cat were correct (indicating flow and correct function of the cat).
I talked to a mechanic buddy and he said that barring some horrific vacuum leak... 1) Maf, 2) Split woodfuf key on timing belt, 3) coil, 4) plugged cat were his ideas in that order (or a combo) given the info of the problem and the ongoing power loss
Yesterday it gave a code P0171 and Ive never been so excited to get a code lol. I tried my friends MAF and the truck had all the power back.
After a few weeks of daily driving on a junk yard maf, ill call it good. BTW a new OEM maf is $750 right now for a 96-98. Swapping to a 99-02 MAF and air box would be far cheaper.