Explorer not idling

[Par5zn2]

I'm new to this forum, so hope I'm posting in the right place. I have a '99 Explorer XLT with 90k miles. This morning, the car would only start if you held down the accelerator pedal for 2k+ rpm, would not hold an idle. No "Check Engine" light when running. When you let off of the accelerator and the engine dropped to Idle speed, the engine would die. Same thing when I tried about 2 hours later. Called AAA for a tow to the dealer. The tow driver decided to try driving my Explorer onto his platform tow vehicle. Explorer started and has run fine. Dealer doesn't know what the problem could be. Dealer thought it might be a bad fuel pump relay so I swapped the #5(fuel pump) relay with the #7(horn) relay. Any suggestions?

 

[Espresso]

Join the club
Search the site for IAC, solenoid purge valve, fuel vapors, charcoal canister
There are tons of threads on here...
Many of us have the same problem

 

[spta97]

Also search for MAF.

 

[jeff96]

My old neon did the same thing once when it got wet under the hood. Had to idle by foot until it dried out. Probably got the computer wet or something.

 

[Par5zn2]

My Explorer is garaged. Also, I live in Northern California where the weather is pretty mild, around 50 degrees in the morning.
I really apprecaite the replies but all of the searches have not been terribly helpful. I think one of the issues is that there are quite a number of possibilities that could be causing this problem. What concerns me is that it could occur agin at a time when my wife really needs the Explorer. One thought that may be a cause is that I have 90k miles and have never changed the fuel filter. Could this be the cause?

 

[spta97]

Supposidly the fuel filter is good for the life of the truck (according to Ford anyway ) I swapped mine out but it really didn't make a difference. I will say that the fuel on the gas tank side was coming out black though so I'm sure a new one didn't hurt.

I can speak about the IAC and the MAF since I've had personal experiance with both. When my IAC (Air Intake Control Valve) went bad my truck would sputter until I warmed it up. I tried cleaning it with electrical parts cleaner ($6 for the spray can at Home Depot) as others did but it didn't work. I ended up getting it from RockAuto.com for $60 and 5 minutes of my time - problem solved.

Recently I started my truck and it would die. It could run for a little bit and when I hit the gas the engine went no where. This was due (of all things) to a spider building a web infront of the MAF (Mass Air Flow Sensor) sensor! The same bottle of electrical parts cleaner came through for me this time (and a q-tip). I think it's possible your problem could be with either one but the easy test is to start it up and unplug the wiring harness to each one (one at a time) and see if the idle changes. If it doesn't the sensor is not doing it's job and needs cleaning or replacing. A Haynes repair manual for $15 will be your best friend with this truck.

I should mention I have the elusive V8, but the principles apply to pretty much all Explorers and modern cars in general.

 

[Par5zn2]

Supposidly the fuel filter is good for the life of the truck (according to Ford anyway ) I swapped mine out but it really didn't make a difference. I will say that the fuel on the gas tank side was coming out black though so I'm sure a new one didn't hurt.

I can speak about the IAC and the MAF since I've had personal experiance with both. When my IAC (Air Intake Control Valve) went bad my truck would sputter until I warmed it up. I tried cleaning it with electrical parts cleaner ($6 for the spray can at Home Depot) as others did but it didn't work. I ended up getting it from RockAuto.com for $60 and 5 minutes of my time - problem solved.

Recently I started my truck and it would die. It could run for a little bit and when I hit the gas the engine went no where. This was due (of all things) to a spider building a web infront of the MAF (Mass Air Flow Sensor) sensor! The same bottle of electrical parts cleaner came through for me this time (and a q-tip). I think it's possible your problem could be with either one but the easy test is to start it up and unplug the wiring harness to each one (one at a time) and see if the idle changes. If it doesn't the sensor is not doing it's job and needs cleaning or replacing. A Haynes repair manual for $15 will be your best friend with this truck.

I should mention I have the elusive V8, but the principles apply to pretty much all Explorers and modern cars in general.

Thanks for the great reply! I have the Haynes manual enroute and it should be here in a few days.

 

[spta97]

No problem. Make sure you get electrical parts cleaner - not WD40 or something that will leave residue. Let us know how you made out. Also, the MAF uses security torx so you might want to pick up a set of those. Either that or file down the nub that prevents the regular torx from working.

 

[Par5zn2]

Got the Haynes manual today. MAF is getting electricity and engine idles lower if the connector is disconnected. Disconnecting IAC results in slightly lower RPM. Haynes manual agrees that the fuel filter should last the life of the car.
Haven't had the starting problem again. Should I leave it alone or check anything else?
Thanks so much for the help!

 

[Par5zn2]

My Check Engine Light now comes on. I assume this is due to my temporarily disconnecting the IAC and MAF. Should I just disconnect the battery negative to reset everything? How long should I leave it disconnected?

 

[spta97]

When I disconnected mine it didn't generate a check engine light. I would go to Autozone and have the code read for free. Even if the light is not on they should still be able to pull the code. Bear in mind too that even though the components seem to be working they could be at only 50% or so. Get the codes read then disconnect the battery, pull off both connecters and clean them, let them dry, and reinstall reconnect the battery. No guarantee that either one of these components is the culprit but they are a good place to start. Also, I would continue until you find the problem - problems seldom fix themselves

 

[spta97]

Do a search for cleaning MAF to get the proceedure.

 

[TPLYNCH]

The fuel filter is not a lifetime item. That should be change every 15-30K miles.

Clean your IAC first. That is usually the cause of the starting problem you described.

 

[mosinman]

Iac

The problem is most definitely your IAC!!!!!!!!!

You can try cleaning it - it sometimes works. Mine kept misbehaving even after cleaning so I just replaced it. Much better than holding in the gas to keep revs up to2k. Much better idle now too.

Make sure to get the gasket while you are at it. $80 or so for the part and the gasket. Remove the plastic SOHC cover and loosen the two bolts holding the IAC in. Remove the blue gasket. (It's one piece, but it looks like two pieces) Install the new gasket and re-install the new or cleaned old one. A nice 15 minute job!

 

[Tom G]

Another vote for the IAC valve