1997 explorer almost stalls until it warms up

[CommandD]

I have a 1997 explorer limited with a v8 and 128k miles on it. For the past couple of days whenever I start it up it almost stalls and then bucks like a horse as it nearly stalls and then revs up repeatedly. This happens in Park, Drive and Reverse. Occasionally is stalls completely.

It seems to happen less often once it is warmed up.

Any thoughts on where I should begin looking for the problem's cause?

Help would be greatly appreciated.

 

[CommandD]

I just took it around the block and it suddenly sped up for a second and then almost stalled and then repeated this pattern a few times.

 

[762mm]

My V6 SOHC did that a long while ago, especially on humid days. Sometimes the truck would die and other times it would suddenly accelerate when my foot was off the gas pedal and cruising at low speeds... once almost causing a collision with a cop car that was fueling up at a gas station, lol! (it looked retarded, but the Ex really behaved like Christine the possessed Caddy at times and seemed to floor the gas pedal by itself at the worst of times: parking lots, red lights, gas stations, etc... but the problem was intermittent and impossible to replicate on purpose. Try to explain THAT to a judge!)

Anyway, I did the spark plugs & spark plug wires, new air / fuel filters tune-up and MAF sensor cleaning tune-up, but it would still do it, albeit now it would do it somewhat "less". So, after reading posts on a few different forums, I went to the Ford dealer and dished out $100 for a new Idle Air Control (IAC) valve. Very easy to change (+- 5 minutes of actual work) and it seemed to cure the "possession" for good. The valve lasted approx. 9 years now and just recently I have ordered a new one from RockAuto (a "Delphi" made unit for about $50) because I have had some of the same symptoms return - namely, the truck dying a few times when I'd put it in gear and the weather was humid this winter. Warning: if you happen to buy a Delphi valve, make sure to reuse the old gasket or to cut out the new one with an exacto knife to match the valve's air holes, because the new gasket provided by Delphi (gray cardboard-like material) has air holes so small that it literally chokes out your engine in idle. Typical GM quality, lol! (I had to put the old Ford gasket back in there and send the Delphi gasket to the trash bin)

While reading up on the subject, I have learned that apparently the IAC valves get "lazy" over time and don't deliver the required air to the motor (slow response). I can attest to the fact that it must be true, as most of the hesitation and engine dying when putting the truck in gear (plus the possessed sudden acceleration) went away with a new IAC valve... twice.

Good luck!

 

[CommandD]

So I took it into the mechanic and they replaced the camshaft synchronizer. I picked it up and five minutes later the problem was back.

I took it back in and they said the part was defective and replaced it and the ignition switch. I picked it up and got it home, but as soon as I started it up the next day the problem appeared right away.

I just dropped it off a third time and specifically asked them to look at the IAC valve.

If it isn't fixed this time around I'll post a video so you all can see what is happening.

 

[CommandD]

It is not the IACC Valve.

Some other info which might be useful:

1.) The car is recently sluggish and requires more gas to get up hills.

2.) I recently almost ran out of gas. Can getting down to empty damage the fuel pump?

3.) The fuel line pressure is normal.

4.) The fuel pump sounds fine

Does this sound like a bad fuel pump. or maybe an o2 sensor?

 

[jbarcus81]

This sounds almost like my issue 100% .. All of a sudden rough idle, almost stalling .. but will surge and almost correct itself .. So, I replaced oxygen sensors and the idle air control valve.. So far nothing.. But I noticed when I would shut it off, start it back up repeatedly it sometimes would stop ... tomorrow I'll be replacing the spark plugs and wires.. if that doesn't fix it.. I'm at a loss just with you...


BUT DRIVES FINE!! What the hell??

 

[CommandD]

I have already had one mechanic give up and I feel the second one is on the verge of giving up too.

I would hate to take it into the local Ford dealer as they would just throw parts at it until something stuck and I might as well as buy a new car at that point.

Do you think I should just run the car until whatever part is on the verge of failing actually breaks? Or would that make the problem worse?

 

[koda2000]

i didn't see any mention of you cleaning the MAF sensor. i believe you can also try unplugging it at idle to see if anything changes.

 

[SoNic67]

It is not the IACC Valve.

Some other info which might be useful:

1.) The car is recently sluggish and requires more gas to get up hills.
Maybe gas tank has rust and crud in it. Uphill will accumulate towards the gas pump pick-up
2.) I recently almost ran out of gas. Can getting down to empty damage the fuel pump?
Fuel pump gets partially cooled by gasoline in the tank. I seldom run with tank below 1/2 full because of that.
3.) The fuel line pressure is normal.
When your truck are level. Maybe when you go uphill is different (see above)? Also, my fuel pump had intermittent functionality, I had to replace it to get rid of that.
4.) The fuel pump sounds fine
Remove it and check the pick-up strainer. Is some labor to drop the tank, but nothing outrageous.
Does this sound like a bad fuel pump. or maybe an o2 sensor?
Rather fuel pump. O2 sensor bad will trow a CEL.

 

[stk33069]

Similar problem with my 99dad sport. It turned out that my PVC cable was sticking. I **** Carb cleaner in there and the problem went away. Couldn't hurt to try. If the problem doesn't get fixed at the mechanics

 

[stk33069]

I Sorry damn phones auto-correct i meant PVC valve

 

[CommandD]

The mechanic replaced the Mass Air Filter and now it is running great!

 

[1992fordgreen]

In the future, these 3 things are the first 3 things to replace with the symptoms you were having CommanD; MAF, (dirty or bad), o2 sensors bank 1 main, and if all else fails, it will most likely be your TPS.

 

[CommandD]

Oops. Doesn't work still.

Now they are checking the onboard computer.

Ugh!

 

[1992fordgreen]

Check your TPS!