I’ve got a 1998 Ranger with 166,000 miles and it’s starting this weird idle at stops where the engine drops about 150 RPM’s and then fluctuates. The problem is intermittent and no pattern as to cold or warm engine. I changed the plugs and wires at 100,000 and the plugs again at 150,000, so the wires have 66,000 and the plugs 16,000. I really don't want to shotgun the plugs, wires and coil pack. I understand that vacuum might have something to do with my problem, any suggestions?

 

Drive it your nearest Autozone if you do not have a code reader and they will scan it for free ,,, just because your check engine ( bulb could be blown ) is not on it does not mean there are no codes,,, sometimes depending on the scan tool and the program used you may get pending codes,,, other words there is a problem that has not turned on the check light yet but soon will,, if you get any codes post them here if not let us know and everyone will try and help you out

 

I have a ScanGuage II, BlueDriver and an Innova 3100 OBDII scanner and neither of them show any codes.

 

Wow this is a little over my head then,,, if you left click I think it's left click on a users name you can message them,,, I would try and message either Pawpaw or Tomw for help,,, these guys have forgot more about these old trucks than I will ever know

 

Thanks for the advice, I was thinking about removing and remounting the coil pack in the event that the contacts are corroded a bit. I called Ford and gave them my model number of the coil pack, they said that a newer one supersedes my eighteen year old model. Factory Motor Parts will sell me a new OEM for just under $61.00 for what it’s worth.

 

talk with Pawpaw or Tomw before throwing parts at it,, I am sure Pawpaw can tell you a couple of test to do on your old coil pack,,, seems like I read a test that Pawpaw talked about with a spray bottle of water or something ,,but I just can not remember all the details,,, like I said those two know 100 times more than me about these old fords

 

just curious when was last tuneup ?????????????

 

Sounds to me like your MAF sensor is contaminated. Get a can of cleaner and remove it and clean it (carefully) and if that don't do it. replace it.

During the cleaning, remove the + cable from the battery and allow about 30 minutes for the ECM to reset itself and then install the cleaned or replacement MAF. That should eliminate the idle issue.

per chance do you use am oiled media air filter? Oiled media filters (like K&N) can contaminate the MAF sensor and cause a weird idle with no codes.

I'd suggest if you do run an oiled media filter to replace it with a dry one.

 

SidecarFlip:
Excellent idea, I do run a K&N filer but have never thought about cleaning the MAF that’s between the filter box and the hose. I have some electrical parts spray that meant for sensitive electronics, I’ll give it a good careful cleaning since that seems to be pretty easy. I’m super careful when I re-oil the K&N, are you a fan of OEM paper media filters? I’ve always stayed away from Fram anything.

Spooktn:
I bought the truck with 88,000, so at 100,000 I changed the plugs and wires and then the plugs again at 150,000. I currently have 166,000……….

 

Wow sounds like Pawpaw and Tomw are not the only smart people on this site ,,, good job Mr SidecarFlip I did not know a K&N filter could mess up the MAF sensor and not show codes

 

I sell K&N products interestingly and I do not use them on my cars with MAF sensors, I found out the hard way. What occurs is, the filter sheds minute particles of filter oil and they get deposited on the MAF sensor elements, causing them to send a false impedance reading.

I replaced the K&N's with Hastings dry pleated filters myself but I believe they are all good. I like K&N not just because I sell them but because they last forever, but they don't work with a MAF sensor, especially if you clean and reoil the filter. Human nature is to over oil and that is where the issue comes in.

I even run K&N on my lawnmower but it don't have a MAF.

MAF and oiled media filters don't get along....

I used CRC MAF Sensor cleaner, you can get it an autozome. I do know that brake cleaner will destroy the housing (it's plastic) so used the specific cleaner. The elenents are very very fragile so don't touch.

Whats happening is the dirty MAF is sending the wrong values to the ECM and the ECM is constantly adjusting the idle trim trying the match the bad values so the engine idles weird. It won't throw a hard code because it's not a fault, just the ECM constantly adjusting the idle trim.

You can check the MAF by unplugging it and throttling up the engine. If you get a check engine light on up throttle, the MAF is good. No light and the issue is elsewhere.

I change my air filters every 30K now. Cabin and air.

Again, no downplaying K&N they make a good product, just not for a MAF in the incoming air stream.

I had to replace the MAF on my wife's Ford, it was too far gone from the oil mist.

 

I have this product called Blue Shower and I just cleaned our suspected MAF, I'll run around Anchorage here for a while and let you know what happened... Be back in a few hours.

 

Sure can, if, you apply too much oil after cleaning the filter, which, I'm guilty of myself. Not just K&N, but any oiled media filter. MAF sensors are very delicate sensors, they don't like an oil film on their wires.

I don't have a clue who Pawpaw or Tomw is and don't care really. I was perusing the posts, saw the issue posted and replied. Nothing more.

 

Yeah and you did it well i think,,, sounds like you might have got this problem fixed,, and I messed up and had to edit my other post,,, I gave credit to the wrong name but I fixed it LOL

 

Not sure a quick clean will do it (might, not sure). I soaked them (we have 2 Fords) in cleaner overnight and pulled the battery (positive cable) for a ECM reset and the one MAF, I had to replace, it would not come online correctly. I got a replacement from Rock Auto along with 2 Hastings pleated filters.

I also cleaned the airbox interior and intake hoses of any residual oil mist during the time I was soaking the MAF's. My 14 Focus readapted fine. My wife's Transit needed a new MAF.

I do, do the Seafoam regimen every 15K on both as a maintrenance item now.

Good luck....