Please Help,
Aprox 4 weeks ago my 98 Ford Expy. 5.4 began to misfire...So I had all the coils, plugs, filters, etc. replaced...A full Tune up.....The Misfiring stopped and my Expy was running great...But today I went with my wife to the grocery store and I sat in the car with the kids for about 20 minutes with the enginge idling and with the AC running...When we began to drive it felt like it was misfiring again and the check engine light began to flicker...after a couple of miles it began to clear up but not 100% we got home and let the car sit for about 4 hours and then I took it for a test drive and it ran fine...Whats up with that? It almost seems like something collected moisture and then it dried out and began to run fine...I remember reading that the #4 cylinder could possibly get dripped on from a radiator hose or something, but I watched it carefully while the engine idled and noticed no drip or moisture there....Anyone have any ideas???

Thanks...

Jason

 

was there a check engine light on

 

You might check at #4 cylinder to see if there is moisture getting to the plug. This might have a heater hose connector over the coil that culd be leaking. I've seen them were the clamp is loose and allowing the hose to leak in that area.

 

Thanks everybody,

I got my exp. in the shop right now and the mechanic said that the code from the check engine light is saying the number 4 misfiring...I had him replace that coil and plugand it is still misfiring..
The mechanic is stumped and has had my exp. for 3 days now....

The check engine light is now off, but it is still misfiring the same as before.

My mechanic said that he will continue to test drive it till the check engine light turns back on, then he will hook it back up to read the code...

Hopefully you guys can give me some advice to pass on to him...

I have watched the hoses above the # 4 coil and I dont see any drips from there...is it possible that he installed a defective coil?

If this helps, it is a constant misfire.....could it be possible fuel injector problem?....or bad plug?....I just had it tuned up a couple of weeks ago and it was running great till now..

 

If it is a constant misfire, have him install an anode lite in the injector plug first, to determine if the pcm is firing it, then into the coil connector, to see if it is firing. Two real quick tests to determine where the problem lies.