Hi, I have a 99 5.4 that is 4x4. I need help trying to diagnose a miss. I usually notice it after the truck warms up for about 5 minutes. It is more noticeable in drive or reverse and very noticeable driving. I have changed all the plugs, all the boots, tested each coil off the truck. I also pulled each plug on each coil while it was running and noticed a difference. I have done a fuel system cleaning, changed the fuel filter. The truck will not throw a code and once in a while it will throw a oxygen sensor slow to respond, but does not come back on after clearing it for a while. I have searched the site and I am coming up with nothing. Any help will gladly be welcomed. Thanks in advance.

 

check around the sides of the intake for coolant. those intakes are notorious.

 

Don't see no coolant leak, any other idea's??

 

How so?