My explorer is dying out on me !

[voivod]

Hey guys,
Ive recently had some trouble with my truck.
It would take a long time (3-4 secs) just to shift from idle and start moving , and some times id hear a bang from under the truck like a backfire.... ive had this problem for around 2 weeks now .
But recently another problem came up, while the car is in idle the rpm will fall down below 500 and the engine will switch off !! even if the car is moving slowly (around 20mph) and if i dont keep my foot on the pedal the rpm quickly falls under 500 and the engine switches off while the car is moving !

This is not safe to drive at all ... so what do you think the problem could be ?
I need to fix this a.s.a.p.

cheers.

 

[voivod]

So anyone able to help ?

 

[daffy]

with the engine dying, I would suggest the IAC (Idle Air Control) vavle first, classic symptom. Search for it here, you will have lots of hits.

As for the other, get a full change of the transmission fluid, see if that helps.

Or post in the transmission forum, there are some very knowledgeable people in there.

 

[kinko]

The IAC is definately your problem for the dead idle. As soon as you let off the pedal, the IAC must feed air to the engine. A properly functioning (not stuck) IAC will change the idle based on the computer's functions, such as high idle while cold, etc. At the least, check your transmission fluid with the dipstick under the hood.

 

[voivod]

The tranny fluid is fine , i checked it earlier .

The problem doesnt happen all the time , but it does happen a lot !

Sometimes also the car backfires when it very slowly tries to shift from the extremely hesitating idle !

 

[Turdle]

Is the "check engine" light on?

Does it come on at all--when you first turn the truck on?

Does the "od off" light flash at all?

 

[voivod]

Is the "check engine" light on?

Does it come on at all--when you first turn the truck on?

Does the "od off" light flash at all?

Nope , nothing like that ever happend

 

[Turdle]

I would try these things-

clean the Maf sensor--( do you by chance have an aftermarket filter?)

replace the IAC valve--seriously-get a new motorcraft unit

check the Throttle position sensor--the voltage curve ( or resistance) should rise and fall steadily as it is moved ( by pulling throttle lever) and drop back to the same value every time it is released--try throttling it (with engine off of course) several times to see if it is flaky. I am suggesting this, because throttle position is monitored by the transmission also--

 

[voivod]

I took the car to a mechanic that has a code scanner , and it gave out the p0505 error code , which is the idle air control system fault .

So it was the IAC indeed , so im thinking of cleaning it first to see if it works ... will a carb cleaner do the job ?

 

[Turdle]

Yes--
take the IAC valve off-try to get the "plunger" inside to move freely.

Good luck,

 

[voivod]

The problem "oddly" turned out to be from MAS sensor !!
whenever i disconnected the sensor , the car would idle unbelievably smooth !
so i got a used one from a 2002 explorer and the hesitation problem was completely solved , and the idle got 60% better ... not as smooth as i want it though .

I also took out the IAC to clean it, under the cap i noticed some spongy like stuff , is that supposed to be there or was it dirt that should have been removed ?

Do you guys think i should return the used MAS and just buy a new one ? i got the used one for half the price , around 45$

 

[Turdle]

It should be fine-
I assume you tried cleaning the old maf sensor?

You might need to disconnect your battery for a while to reset the PCM-

I haven't ever removed the cap from an IAC valve, I only cleaned the air passages, and freed the valve plunger