Have a 1990 5.8 F250 manual. Super clean truck only 115k on it no rust so she needs to run again. She starts up but very quickly surges then drops the tach is jumping around. If I floor it it sputters but never dies out just sputters. If I try to drive it there is no power same rough sputtering mess. After about 10 minutes tho it starts to smooth out and runs fine. Mileage is down maybe 7-8 mpg. Plugs are new, TPS new, IAC new, cap rotor dizzy and wires are new. Engine Temp sensor getting 22k ohm when cold didn't test it hot or warming up Any ideas let me know Im going to test for vac leaks in the am as just got the tool tonight but visually I checked all and everything looks good. One note is my dizzy crapped out in the fall and it sat all winter spring and just fixed that issue to have this issue. Fuel filter is only a year I put fresh gas in with a can of seafoam so gas should be good I've burned through 6 gallons so far

 

Before you threw money at it did you check for trouble codes?

 

No CEL and code reader not picking anything up. Maybe it's not working have the basic $25 Ford reader.