I've got an 88 F150, I-6, 5 speed that one week ago started running really bad It cranks up fine and idles fine, but with a slight miss. When you gas it, it sounds like an old beater and misses really bad, but not like a hard miss. If I up shift too quickly, it'll really start stumbling and bucking (but it'll keep going). Otherwise it's still taking me to work, I cruise at 65, 2000 RPM but with a noticeable miss (much much worse with AC on). I've replaced plugs, wires, rotor (inspected rotor cap, it looked OK), coil, fuel pressure reg, and air filter. I cleaned my plenum, and IAC with cleaner and gutted my CAT. I convinced myself the exhaust flow wasn't very good (its better now). I've got dual tanks and the rear tank quit working this past July, so I've been only using the front tank. Last night I pulled the fuel lines going into the tank switching unit and turned the key on, no gas spewed at all, despite switching from front to rear, so I pulled the rear tank off and will replace the internal pump tonight on the rear tank. If that fixes it I'll do the front tank. If it doesn't, I'm thinking the stator or pickup coil might be bad, but (I should have mentioned earlier) I get CODES, 11 system pass and 34 EGR out specs (my EGR is plated off). I think the stator should throw a code if its bad and I noticed a condensor looking gizmo next to the coil, maybe it would cause this? I can't determine if this is a fuel or ignition problem, hopefully not mechanical. TOnight, I'll put the tank back and check compression. Thanks for taking time to read this long post. I'm at wits end, any suggestion would be appreciated.

 

I meant to mention, my mileage is 201,000 miles (oil changed within 2000 miles). Gauges show no problems with alt, temp or oil pressure..., Check engine light does not come on, to indicate a problem.