Ford Explorer Rough Idle / Stalls / Sputters

[splatmike]

I have a rough idle / stalling / problem with my 1992 92 Ford Explorer 4.0L . I bought it a few months ago. (Was running OK but didn't have much power). I noticed one day that I had a spark plug wiggling in the block. I then did two things. 1st - I replaced all 6 plugs with AC Delco's. The other 5 plugs could be turned out by hand. I first gapped them at .045 . I then changed the serpentine belt and routed it correctly. (On the pulley on the lower passenger side, they had routed it on the wrong side). The Explorer, in the morning, would start fine - idle up then start relaxing. Would start sounding like 3 cylinders were only firing then die if gas was not applied at this point. With a little more drag on the motor from being in gear, just made it worse. You would have to work both the brake and gas just to get it out to the street. Then it would seem to run fine for seven blocks. But when I hit a stoplight, it died. After it warmed up a little, it would seem to run, idle like it should. I then gapped the plugs to .054 . Same problems. On the highway, the CEL would be on about 1/2 the time but would seem to run OK. I noticed a small vacuum leak, on a line where it entered the (big round thingabob) above where the master cylinder is attached. I sealed the grommet where this vacumm hose entered the big round thingabob). It did seem to run a little better. But the problem still exists. I have pulled and checked all the new plugs for cracks, made sure all boots were on good, cleaned my MAF with brake cleaner, .....????..... Any ideas ??
Thanks
Nebraska

[exploded99]

Originally Posted by splatmike

I have a rough idle / stalling / problem with my 1992 92 Ford Explorer 4.0L . Nebraska

First, check all your vacuum lines for leaks, make sure there are none. Once you are sure there are no vacuum leaks, pull your idle air control valve off and clean it. If that helps, but doesn't really fix it, I would go ahead and replace it. About 50 bucks at the parts store.

[B33p3r]

Check your air intake duct also. Make sure it is tight to the intake. If air sucks in from a bad seal it bypasses the MAF and you get bad readings and a bad ride.

[splatmike]

OK.......So I broke down and bought an MAF. After I had the MAF in and was reassembling, I noticed something. I took note and took it for a drive. Same problem. I then grabbed a gallon bag zip lock and some strapping tape.
RUNS PERFECT NOW !!
I had a split in the air tube INBETWEEN the MAF and the intake of the engine. This split was on the bottom side of the tube out of view. Some air was bypassing the MAF thus giving it really 'funny' readings at a cold start. It must have opened up when I moved it to change the serpentine belt.
If this helps ANYONE else, please post a response. I am quite curious how much time/money this saved anyone !
Thanks for reading
splatmike

[splatmike]

Originally Posted by B33p3r

Check your air intake duct also. Make sure it is tight to the intake. If air sucks in from a bad seal it bypasses the MAF and you get bad readings and a bad ride.

******************
Oh how I wish I was a little lazier......I didn't read you response till this morning ! You had it nailed. Would've saved me the cost of a MAF.
Splatmike