Posted 02 April 2011 - 11:08 AM
I need help, please. i have a 98 ford f150 xlt xtended cab 4x4. has a triton 4.6 liter v8 with 129,000 miles. for last month or so, it has been running rough when first started. engine hesitates at idle and then really hesitates when first accelerating. gets better when it gets warm, but not completely. had motorcraft platinum plugs and wires installed 12000 miles ago. ran two cans of seafoam through two consecutive tanks of fuel thinking i had gotten bad gas. no help. on a really cold day ( 40 in florida ) it was missing really bad and backfired within a mile of driving. check engine light began flashing then went solid. took it to goodyear and scanned it. code 305 misfire in #5 cylinder. took it home and changed the #5 plug. check engine light did not reset. changed fuel filter. no change. had engine light turned off and codes cleared. problem continued, but no check engine light came back on. took it to ford dealer and was told i needed to drive it til check engine light came back on to get a code. had spark plugs changed last week. went with autolite platinums. mechanic said he didnt see a real problem with old plugs. still have same problem. changed pcv valve. looked for signs of vacumn leak, but could not find one. its driving me crazy. especially when i feel it hesitate in the brake pedal when im idling. feels like it wants to cut off, but doesnt. ive been told so many things from: cylinder sticking, plug wires, coil packs, etc. nobody appears like they want to diagnose the problem without having a code to go by. i thank anyone in advance for suggestions.