02 Mountaineer - rough idle, dying at idle, hesitating on acceleration

[rmcbri01]

Started with the SES light coming on and the above issues. Code came back indicating the DPFE sensor needed replaced (code 1400, possibly, can't remember for certain.) Changed sensor and SES light went out but issues remained. Mechanic scanned and came back showing cylinder 4 had misfired thousands of times. Pulled the spark plug boot and swapped it with cylinder 6 to make sure the boot was bad. Scanner showed no misfirings at all but still had the above issues, so no boots were replaced.

Did a tune-up and replaced plugs and wires. Still having the same issues at this time.

I've noticed it's worse when the engine is cold (roughly the first 10-15 minutes of driving it after it's been sitting for an extended period of time.) Once it's warm, the frequency of the issues decreases considerably but don't go away completely.

Any thoughts at all? Thanks in advance.

 

[fusseli]

What engine?

 

[rmcbri01]

What engine?

It's the 4.6 V8

 

[rmcknight]

did you replace the coil(s)?
You should compression test #6 and another one to compare. If thats fine and it probably is, then replace your injectors.

 

[rmcbri01]

did you replace the coil(s)?
You should compression test #6 and another one to compare. If thats fine and it probably is, then replace your injectors.

Thanks for the tips. I'll talk to my mechanic about taking a look at those items.