2004 5.4L Rough Idle

[txtrp70]

On the highway two hours from home and my Expy CEL starts flashing and I start losing power while on the highway. Stopped at nearest Autozone and code indicated P0307, Misfire #7. Didnt have tools to repair, so I drove home. Got home researched all the forums in regards and replaced the COP and spark plug. Still a rough idle, checked code and got a P0406 EGR Sensor A High circuit. Replaced EGR, EGR solenoid, DPFE Sensor, cleaned throttle body, cleaned MAF, cleaned IAC, replaced fuel filter, replaced PCV, and changed oil and oil filter. Replaced just about every vaccum hose and elbow. Sprayed carb cleaner to verify no vaccum leaks. Still idles rough with no codes. Idles at 800rpm on start up, drops to 600rpm when put in gear. Can't put a load on it like A/C or it almost dies. I did replace the plug with a Bosch Platinum non gapable instead of an autolite. Any ideas? Im not getting any codes.

 

[X.handyman89.X]

Hi fellow Texan! You should check the fuel presure and see if your getting enough fuel to the engine. If you are getting good fuel pressure, i would check all the coils and see if any of them are bad.

 

[2k3Expy]

can you check pending codes with your scanner? Not that it should matter but I have found the OEM plugs always work best.

 

[Tigster]

I was having something like that, there was a short in the wiring harness. I took it to a local shop and 140 bucks later it is all fixed.