rough idle newbie ?

[johnsterling]

Just bought a used 95 XLT the other day and I have been working non-stop to get all the minor bugs worked out.

The rig has 135,000 orginal miles and I purchased it form the orginal owner. I have all the records back to 1995, with almost everything replaced since then, new trans, new steering, new front wheel bearings, new MAS and T- body. (fuel filter is new)

Anyway, the minor problem is a rough idle hot or cold.

I have moved up to 92 octane, added FI cleaner. no change. cleaned the MAS, Replaced both O2's, Replaced IAC. no change. (they all appeared to be the original equipment, so 135k it is time to replace O2's right?) TB and MAS are dealer installed new as of the last 30k miles.

I haven't actually pulled the plugs, as they are very new motorcraft installed at the dealer. I did replace the original plug wires-no change?

The motor seems to run very strong and pulls very hard, there is no roughness once you start moving forward with just a minimal pedal push. The idle starts out at say 1,000 and quickly moves to 700rpm where it actually stays. no rpm movement either way. I checked for broken motor mount, doesn't seem to be the case?

Anyway, any ideas? could it still be fuel injectors? maybe I would have to take the intake apart and manually clean them?

Any ideas? and no CEL!?

John Sterling

 

[onelasttry]

man, i know what those sensors cost and you have a pretty hefty investment to not have any results. You've done everything i would have, but perhaps there is more.....

 

[section525]

I'd check the coil pack!

Welcome to the forum, John!

 

[johnsterling]

Thanks for the ideas!

Yes it is puzzling and it is a ford, just kidding. Napa parts guy calls it an exploder, hehe.

So the list of things I will try today include:

Pull some spark plugs just to double check, Spray some soapy water on the entire upper end and manifold area to see or listen for and rpm changes as to the possiblity of manifold leaks or vacumn line leaks. So far most of the rubber under the hood appears to be in good shape for a 1995 with a 135,000 miles. I used to live in california where most of the rubber would have been dried out by now. Since this XLT has lived 99.9% percent of it's live next to lake washington, the issue under the hood is more to do with stopping rust and I think the gasket and hose issues may be nonexistent at this point in time.

Drove the wife to the park and ride this morning, it is hard for me to gauge the performance of the rig as I purchased it just the other day. Anyway, there seems to be plenty of power as it seems to pull very strong.

I have been using the cheap gunk flush on my nissan for over ten years and the engine has almost 250,000 miles and passes smog by a huge margin. Funny I will use almost any old oil in the nissan will no problem at all. I WILL NOT USE the teflon or prolong crap, I saw some 3 bearing engineering reports of slick 50 and these type of additives do more harm then good in my opinion.

So I haved flushed the engine just before the recent oil change the other day, just for good measure. There is basically no lifter noise and inside of the tail pipe you could eat off. no smoke or oil or gas smell or residue of any kind.

I am somewhat tempted to remove the cats or cat. just to look inside. I just can't seem to justify this as strong as the rig seems to pull. I am thinking of having some friends at a car dealership drive it, as they may be able to make a better comparsion of how well or strong the rig is really running. This is difficult for me to gage, considering I purchased used.

I guess I will look into the de-carboning the upper end thing some more along with cleaning the injectors without removal?

After this I guess I will have to break out the omn meter and begin testing staring with the coil pack.

 

[EliteConcept]

maybe clean the MAF sensor with some canned air...the filimaent inside can becoem dirty after 30k, i try to clean mine every year.

 

[TPLYNCH]

I wouldn't run 92. Go back to 87 and troubleshoot from there. The 92 will cause carbon buildup and just empty your wallet quicker.... Try tightening your intake manifold bolts. As an aside, is there any difference in the idle if you have the HVAC controls off vs A/C or defrost settings?

 

[Jason_25]

Good luck with the rough idle and please keep us informed. I have attempted to remedy the rough idle on my 95 since I got it with 69K miles. I have replaced virtually every sensor expcet for a few with abolsutely no success. Runs great, idles rough.

 

[DonM]

I had the same problem, the Fix was installing an Apten Chip. Took care of my rough idle.

So that would mean my computer was the problem.

 

[johnsterling]

Tried sea foam yesterday, poured the whole can down the mainfold without the engine running. *I hate reading directions on things*. Locked the entire engine up- Just kidding . Sea foam did very little overall, I believe it is a good idea to use it and follow the directions. But the only reason it did very little is possibly there wasn't much to do in my engine.

So for right know I have to live with the rough idle .

I did finish installing the trans cooler and flushed the entire trans out, didn't change the filter as there was no need considering the the trans is ford factory new 30,000 miles ago and the old trans fluid coming out looked almost the same as the new going in.

Rough idle still bugs me though, but the good news is that I only paid $4,200 for this loaded XLT one owner rig with $7,000 in new dealer parts in the last 3 years ! So I guess I can't complain too much. Kelly wholesale on the april dealer CD is $5,600 with the high miles! True story, old owner called me yesterday about a registration issue, he then starts lamenting about his unhappiness over the brand new toyota he purchased! I wishes he kept his Explorer and didn't buy the new rig!

(I don't like buying used fords unless it has just had a new trans and new power steering installed! not kidding)

One of these weekends I guess I may pull the plugs and pull the cat just to see what they look like, but for right now it is to much fun to drive and pulls to strong to worrry. I understand the other drivers concerns as they honk their horns at me, but hey I am driving my SUV and am now KING OF THE ROAD!

Replacing/upgrading the chip sounds like a good idea as well. I am actually looking forward to getting a smog check, as the readings may actually help me to determine where the problem may be coming from?

NO SH%T, I ALMOST FORGOT! There is something very strange and puzzling going on under the hood! the freaking A/C cycles on and off for NO reason????? My A/C is haunted by demons! *There is basically no difference in idle a/c on or off, so the idle control thingy for a/c is working great and the a/c actually works great as well.* But the A/C pump just goes on and off for no reason?????

hope everyone is having a great day!

John Sterling

 

[TPLYNCH]

NO SH%T, I ALMOST FORGOT! There is something very strange and puzzling going on under the hood! the freaking A/C cycles on and off for NO reason????? My A/C is haunted by demons! *There is basically no difference in idle a/c on or off, so the idle control thingy for a/c is working great and the a/c actually works great as well.* But the A/C pump just goes on and off for no reason?????

Your Ex is not possesed... Compressor will run in all HVAC settings EXCEPT "off", "panel" and ('99+ models) "floor" as long as the temp is above ~ 50 degrees (can't remember the exact termp, sorry).

 

[johnnyt73]

I'm having the same rough idle -- it sits around 700-800, then drops... it seems to "kick forward" while stopped at a light or stop sign. It is powerful enough that my brakes sometimes groan.

I have noticed the A/C compressor kicking on and off, and I think it may have something to do with that. But, I haven't tried cleaning the MAF either. The only other strangeness going on right now is that the check engine light kicks on after 2-3 hours of continuous driving. Someone suggested it could be one of the emissions sensors?

BTW: '95 XLT, 153,000 miles and counting... I've owned it since 29000.

 

[DonM]

Change the 02 sensors.

 

[johnnyt73]

Local dealer said O2 sensors are $97 bucks each... ugh...

Thanks for the tip, I'm definitely going to have the codes read on this before doing anything.

 

[Robert]

If you end up needing new O2 sensors, you can get them at Autozone for $50 each. Be sure and get the Bosch OEM sensors. They also have Bosch generic sensors. The generic ones will require you to take the connector off your original ones and use it on the new one since they only have bare wires. The OEM sensors will have the correct connector already installed. Just screw the new O2 sensor in place of the old one and plug the connector in to the connector plug. The OEM sensors are also $10 cheaper than the generic version.

 

[DonM]

You can also get the O2 sensors at fordpartsnetwork.com for cheaper.

With 153,000 miles they will most likely have to be changed.

Free scan a Autozone.

 

[oceanworker]

check every and I mean every vacuum hose for a leak.

 

[johnsterling]

Well the manifold nuts are all very tight as far as I can tell and I just checked to see if there where any old codes. Nothing showing, all clear 111.

I think I will bench test some coil packs at a local junk yard to get an idea of what the omhs sould be for all the different connections on different used coil packs. Then I will test mine and compare ranges and values. I have had some success with this method before in the past. In other words if the values and omh ranges are all very similar I will assume the coil pack is ok. Like I said this bench test method has saved me $100's in the past and the parts house or wrecking yard doesn't care as long as the part is not installed.

Additionally the way the fuel filter is basically brand new, but the FPR may be 130,000 miles old???? Maybe I should test the fuel presure at idle?

 

[whj812]

I had the same problem on my X. I bought it about a year ago. When I got it, the engine idled really rough, and it made the "marbles in a can sound". I just started doing minor things to it, like cleaning the MAF, IAC. That seemed to help a little, but it was still there. I then bought a MAC intake kit, changed the spark plugs, and wires, and cleaned the injectors. NOW the truck runs so smooth! I just now need to work on this small rattle comming from the exhaust. I think it might be a heat shield.

 

[cnote76]

me tooo

I have also had this problem with the idle at 7-800 then when sitting at a stop in traffic it revs up to 1100 and feels like it is trying to take off on me. I replaced the IAC yesterday and it seemed to work....yesterday. Today it is starting to do it again. Should I have autozone check my codes? All of this right after I just got it back from an a4ld rebuild. I am going to check the MAS now. For those of you whom experienced this dilemma. Is it a safe bet to go ahead and get new o2's. Or replace one here and there and hope that I find the right one? Pending it is an o2 problem.

Please help

 

[johnsterling]

whj812, did you have the injectors cleaned where they run the car with the injectors hooked up to a cleaning system? or was it down more by the cleaner in the tank kind of thing?

I talked to a local Ford dealer yesterday, and they did claim to some extend that this engines do idle slighty rough. I then went out and talked to the actual techs, there thinking is similar to the service writers thinking. They would clean the fuel injectors first and run them through some tests.

Had to change the title today, so we went for the smog check. I was somewhat worried that we would fail on the HC at idle. PASSED!

Funny thing is, as far as I can tell, The emmisions report today was actually lower across the board then when the rig passed in 1997 test. LESS CO, LESS CO2 and LESS HC's

More and more i am thinking we will be living with the rough idle.