Runs rough, badly, sometimes horrible

[CHEVELLE]

Hello, I have a 2001 5.0 Explorer. I've been having this problem for about a month and a half to two months. I have 43,000 miles on it. When Explorer idles in park decently, when in drive or reverse it really runs rough like it might stall or when you hit 45-50 mph it really acts up and occasionally a popping sound occurs once or twice at these speeds (sounds like from pass. side under hood). I have changed the fuel filter a month ago, cleaned the IAC by spraying elec. parts cleaner spray. I have tried fuel injector cleaner/fuel system cleaner fuel additives several times. There is a noticeable difference when these have been added. When they're not in it runs badly again! It was checked at Auto Zone, they said Cyl. 8 misfire. I changed the plug also. That was a month ago and haven't had it ran again. Right now I'm getting that sulfur smell and it's running rough again. What do you think guys? Thank you for any input!!

 

[TPLYNCH]

Clean the MAF sensor. Also, look for vacuum leaks, check the EGR tubes and you may also want to check your catalytic converters.

 

[CHEVELLE]

Thanks, I'm gonna try to check the egr and tubes out this weekend. It's just strange that it runs so much better with injector cleaner, making me think that, that could be the issue.

 

[WillieTD]

Check your TPS, too. Mine ran rough until I replaced it. EGR valve failure will also make it run rough but you would have a CEL for that.

 

[CHEVELLE]

Anybody think plug wires and plugs could cause this stumbling on a 3 1/2 year old car with 43,000 miles? I don't want to keep buying parts if it's not needed. CEL blinks if you put your foot in it with that sulfur/egg type smell for a minute or so, then it will stay on. Cleaned MAF, IAC, ran seafoam thru BB vac. hose. Seafoam helped for about 5 miles then back to the same old same old. After I ran the seafoam I took her out for a spin. When I got on the road there was a metal type rattle from the engine for about 5 seconds. My best description is sounded similiar to sticking something metal in a metal bladed fan.Then it went away. I have a cyl misfire on cyl 8. Could this be the inj.? I pulled that plug and it looked like it had oil or something brown on it. Confused and need explorer fixed soon. Thanks for any input!

 

[cbr1100crash]

Hey CHEVELLE, did u fix it yet? I had the same exact problem a few years ago. It was the plug wire that contacted with the exhaust maifold and burned through to the actual wire. Replaced all 8 wires and it ran perfect.