5.0 misfire?

[G0ldiE*99]

I've got a 99 explorer 5.0 that intermittently misses... going down the road u hit the gas and it stutters but can most of the time clear up when u get down on it.... it doesn't do it all the time but when it happens, seems to get worse over time. I've changed ignition coils, wires, plugs, mass air flow, idle air and it got worse! I put my mass air flow back in and it got a little bit better. Any suggestions?

 

[Centaurus5.0]

Vacuum Leak?

Does it only stutter right when you hit the gas?

 

[G0ldiE*99]

------- no it will do it even when idling sometimes

 

[Centaurus5.0]

So it comes and goes? Does it run perfectly fine for a bit then starts acting up or is it always sputtering, whether hot cold, low or high rpm, light or full throttle? When it's idling, does it act like the engine is about to die (sputter out) then revs high and run well for a bit?

 

[G0ldiE*99]

Yeah it runs great for a while then u stop at light and u can and u can here the engine just change it's runs great then It picks up a studder most the time I can hammer down on it and it will clear up my thoughts r maf,ecm, or injectors but it so intermittenly ....it kinda happened over time it got worse since I got the truck before it barley did it it was a miss once and a blue moon now it's doing it everyday sometimes on startup

 

[G0ldiE*99]

The truck has never stalled or shutdown it just started doing it on idle never originally. I thought it got bad gas during the hurricanes but it hasn't got better when I added plugs and wire I thought it was fixed bout a week later it started again same with the coils so I changed the mass and iac and it was barely drivable I change the mass back out and it runs good here and there

 

[Turdle]

You might try a new fuel filter, and some fuel injector cleaning stuff. Check fuel pressure and report back. Idle fuel pressure and full throttle blip pressure please.

Does the check engine light turn on with key on and turn off once engine is running? have you seen it light up at all?

 

[CDW6212R]

Ditto, do all of the things mentioned above. Its' likely one of them, and even something you've already done before. Keep tabs on the fuel pressure, you might need to check that regularly.

I had a similar issue that got worse over time. The start was a bad coil that took me a year to find(I had new coil packs just prior, so checked those last). My truck had gone un-driven for many months at a time, and it eventually became the gas tank itself, corrosion slowly filled the pump sock, and lowered pressure. The fuel filter I swapped 2-3 times, always looked okay, but the tank was bad.

Check all vacuum lines carefully, all of them. Be careful and tedious in checking things often, hopefully you find it before anything is hurt.

 

[G0ldiE*99]

Fuel pressure on idle is around 62 lbs the check engine lights on the last time I checked it was cause of bad o2 sensor and it said misfire#2 I hauled two car this weekend ran beautifully as soon as I dropped the trailer it missed for a few miles