rough idel NOT MAF..what is it

[EliteConcept]

my 92 idels really rough i cleaned my MAF and that helped some, but it still idels rough.
I have 3 new spark plugs just recently installed, i havent yet gotten to the ones on the passengers side...
I have a K&N air filter that is brand new also.
any ideas at what it could be that is making my X idel rough??
thanks guys

 

[Jason_25]

Could be your spark plug wires also. While you're doing the plugs you should probably change those too. Jacobs and Magnecor make good sets.

 

[EliteConcept]

what effect do the plug wires have on the plug or plug preformace? and engine

 

[Jason_25]

They have alot of effect one engine performance. If they get old and cracked (usually due to heat), then they can leak spark energy, thereby leading to a less hot spark. So if you change them they won't leak energy anymore. Maybe someone else can shed a little light on this subject. Good luck.

 

[oahrens]

How is it at idle?
puttering....misfiring....etc.
and what do the rpm's do on flat ground?

Quick list...fuel filter, wires, bad gas, exhaust.

 

[MikeTEC]

I had a similar problem.Try changing brands of gasoline. Also regular idles more smoothly for me than higher octane, but pings some. I have found the major brands like Exxon and Texaco do well in my Explorer. Changing gasoline fixed my idle problem. Mike

 

[TPLYNCH]

Easiest thing to check for are vacuum leaks. Check and make sure that none of the caps have popped off the "octopus" and that there are no cracks in the lines themselves. Common problem on older ex's and causes trouble like you're having.

 

[EliteConcept]

the octopus part you refer to where is that at?

 

[FMNavajo]

TPLYNCH mentioned the octopus, this is where all the vacumn lines are attached to the upper intake manifold. Open the hood and move around to the drivers side of the engine compartment. You said you changed the drivers side spark plugs? find the plug closest to the driver, (#6), and go straight up and you'll find a....thing that looks like an octopus. It has about 8 vacumn lines plugged in to it. All the holes should have a cap or a hose plugged in to it.

good luck,
FM

 

[EliteConcept]

alright, that was a great decription of where to check!!
I'm gonna check that out today and see if everything looks ok.
I'll let you guys know what i find.
Could i also be getting such a bad idel if my spark plugs on the passengers side are really bad??? because, i just changed the shocks recently and they were stock because no one probably wanted to mess with them before, and the spark plugs don't look very fun to mess with.
Could 3 spark plugs that have been in there since 92 cause a really bad idel?? Also I'd change the wires if i had the 3 plugs on the passengers side changed.

 

[FMNavajo]

Elite, when you changed the plugs on the drivers side, 4, 5 and 6, how did 5 look, it's the middle one. Did it seem to have more carbon build up than the others? I'm just asking because when I started working on mine that was the first search I did on this site. It's caused by a combination of things, Fuel Pressure Regulator, (FPR), O2 sensor, and a leaking or improperly torqued lower intake manifold. I ended up getting all the parts and changing out the lower intake mainfold gasket, the O2 sensor and FPR and my gas mileage jumped up considerably and the truck ran so much better after getting a chance to clean out both manifolds and all the throttle body components.

I believe there is procedures on the Explorer tips section ot this site or you can use the Haynes manual which is very easy to follow.

FM

 

[EliteConcept]

no i can't really say that the middle spark plug had any more Build up on it then the 2 others.
There might have been a slight differnece but not alot.
I also checked out the "octopus" and everything seems to be in working order there.

 

[oahrens]

OK...
First thing is refill with good gas then reset the computer. If you cleaned/replaced anything to do with the fuel/air/exhaust then you have to reset to relearn the fuel/air mixture.

 

[EliteConcept]

i did that when i changed my oil last week.
because i cleaned off the battery posts.

 

[superman5787]

I had the EXACT same problem with my '91. Try this. Go to your power brake booster. See the hose going in to it? Pull it out and put your finger over it. Now get someone to push the brakes... See if it idles bad or not. See, my problem was that my brake booster was going bad and I had a vacuum leak INSIDE the brake booster. I had a new one put on and it was all fixed up. Before I had it replaced, I just plugged the line to the booster and it ran wonderfully like that with no power brakes for 2 weeks. Just try it, you might be surprised.

 

[EliteConcept]

superman5787
when you did this, did you have any lights on on your dash, brake, check engine, any kind of visual???

 

[roadkill]

FYI

My rough idle went away the same time I fixed my engine running too cool. Replaced the thermostat, but the temp was still reading low on the gauge. Turned out it was the temp sending unit. Replaced it, the temp "read" like it's supposed to. AND, the computer was getting the right info for idling.

Might not be your case, but it helped me!

Good luck!

 

[oahrens]

Hey guys...

Check the TPS for sure like roadkill said. Also, at idle put your hand over the tailpipe and see if it's choppy or steady...Could be a stuck throttle body or clogged exhaust......

Keep on postin'

 

[EliteConcept]

superman,
i was changing my PCV valve and i hit this brake booster line, i think thats what it is...well i bumped it a little and heard a air leaking sound.
if i pull on the rubber tubing lightly i hear it also.
but my brakes work fine!
should i replace this rubber tubing/
thanks