Hello,
I've been dealing with an issue for a while now. My '07 Navigator has 145k on it and the engine is running terrible. I do not have the exact codes as I have been dealing with it for so long I have forgotten them! The codes, as read by the guy at Autozone are for a misfire on cylinder 4 and excessive emissions on cylinder 4.
All plugs were changed at about 95K and cylinder 4 had a new plug and COP when first diagnosed by Autozone.
I swapped the new COP and plug with cylinder 3. The issue stayed with cylinder 4.
Under hard acceleration it will kick in and out, kind of pulsing.
The engine also has a constant ticking and has had it for at least 50k miles. I always figured it was an exhaust leak.

Any help on this would be greatly appreciated.

Jeff

 

Get the EXACT codes, otherwise you're just wasting everyone's time.