Hi all,

First post. Long-time lurker.

Recently bought a 2000 Ford Ranger XLT 4x4 3.0 Flex-Fuel w/ 5-speed standard transmission. Been a pain in the butt since day one. Had a blown head gasket when I bought it, replaced those a few weeks ago. Did the cam synchronizer, coolant temp sensor (@ thermostat housing), thermostat, waterpump, timing chain/sprockets, EGR pressure sensor (old one snapped when trying to remove one of the hoses), and radiator while I was in there. (Can't say how she behaved before I did all the work. Didn't drive her much.)

Everything seemed fine until I recently put a real "load" on the thing. Driving into a strong headwind with the bed full of a washer and dryer, she would hiccup at speed. I couldn't maintain 70mph. If I let off the gas and then gave it all, she would come back up, for a while, before doing the same thing again. After getting off the freeway at my destination going 25mph and the pedal floored, there was a lot of hesitation, would lurch a little, then hesitate for several seconds, lurch again. About this time, I got the P0172 rich code. Scanned the truck, MAF sensor was all over the place. At idle, was showing 70+liters/min, so replaced the MAF. Went down to ~3l/min, thought the problem was solved. Until last night. Got the following codes:

P0172 - Too Rich
P0175 - Too Rich
P1132 - O2 Reading Rich
P1152 - O2 Reading Rich

I've checked for vacuum leaks (propane/carb cleaner) and found none. Checked the fuel pressure at the fuel rail, showing about 63PSI both at idle and at ~3000RPM. It's obviously running rich, doing about 10mpg, lots of soot coming out the exhaust, and it stinks like sulphur. I assume my cat is toast at this point, but would like to get this running rich situation handled before throwing a new cat into the equation.

Any help or suggestions are greatly appreciated.