Solved 98 mountaineer 5.0 help please!

[00mountaineer4.0]

Hi all, been a few years since i visited this forum. I loved my 2000 mountaineer 4.0 (screen name) until it was stolen and totaled. Well, I always wanted another with a 5.0 and i recently purchased one. The seller said it needed a tune up, it had a bad miss and an exhaust leak. I drove it home without any issues. I just finished replacing plugs and wires, i plan on fixing the exhaust leak this weekend. The problem i am having is the apparant miss at idle did not go away with new plugs and wires and now im worried. I can hear it in the tail pipe and the car shakes pretty violently at idle with a rythm but seems to clear up off idle. Any suggestions what to check next? there is no CEL light on. There is no mechanical noise to speak of under the hood, so hopefully it isn't an internal problem. No noticeable smoke either. is this a common problem? What should i check next? thanks for any help! I would love to get it back on the road!

 

[bill06447]

A few things come to mind-burnt valve? Leaking EGR? Faulty or dirty IAC valve? I'd start simple, pull the IAC and clean the crap off the plunger

Bill

 

[00mountaineer4.0]

okay thanks bill

 

[00mountaineer4.0]

i did the old dollar bill against the tailpipe trick. i believe the problem is a burnt valve. dammit.

 

[kevinspann]

Are the plug wires routed correctly? It'll run like complete **** even with 2 of them swapped.

 

[koda2000]

the only real way to determine the condition of the valves (and engine health in general) is with a compression test. don't freak-out just yet.

and do check the plug wires to make sure they're on right. if you assumed the PO had them on right and copied his routing they might be on wrong.

 

[00mountaineer4.0]

yes i checked the plug wires and put new wires and plugs they are routed correctly. I am going to clean the IAC and check coil packs tomorrow. There is virtually no room on the passenger side under the hood, fun fun!

also some good news, i misunderstood the burnt valve test, i freaked out a little soon i think. iT doesnt suck the paper at all


thanks for all the help guys, i will report back

 

[00mountaineer4.0]

it was a bad coil pack. thanks guys

 

[istroo]

Glad you found it and thanks for the update!