Stalls in Drive (1998 Explorer Sport SOHC)

[TomCat_Ford]

Well this is my first post here on these forums. Yesterday afternoon I bought a 1998 Ford Explorer Sport with the 4.0L SOHC engine and an automatic transmission from a private party in my state. The reason they were selling the vehicle is because of this very problem- they couldn't afford to figure out what the problem was and have it fixed.

The problem explained... when the engine is cold, it works perfectly fine. The idle is perfect, it sounds good, it accelerates as it should, etc. Once the engine warms up, however, it can stall when approaching a stop sign, light, etc. After the engine has stalled, you can put it in park, turn the ignition key off, turn it back on, and the engine will fire right up (immediately with zero hesitation). At this point it is idling as it should and acting just fine. But when you go to put it in drive, it shuts down. I even tried double footing it so I could rev the engine up a little bit to see if that would help, but it simply shuts down... just as if I had turned the key off at the very moment I get the shifter lever in drive. Now here's the weird part; if I put in reverse, 1, or 2, it works just fine. There are no problems whatsoever in any of those gears. The only time it will stall is if the vehicle is in drive. From a stop, I was unable to get the vehicle to move in D after the engine was warm. To get it on the trailer, I simply put it in one of the other gears and drove inside the trailer after I bought it.

Any thoughts as to what might be causing this issue?

Thanks for any and all help.


-TomCat

 

[TomCat_Ford]

I did some more testing today. After I fixed some other things on the car, I pulled it out of the garage and let the engine warm up (it's 12 degrees F outside according to the temp gauge). After the engine had been running for 15-20 minutes, I tried it out. From park to drive was fine... no stall. I then took it out for a spin. I took her up to around 50-55mph and came to a complete stop about 1.5 miles from home... no stall. I turned around, put it in reverse, backed, up, and tried putting it in drive again... no stall. I drove another mile or so, turned around, and it stalled that time (roughly 2.5 miles from home). I then put it in neutral, fired it back up, put it in drive, and it stalled. The engine just abruptly stops as though the ignition key was turned off. So I put it in 2, got it completely turned around, and got it up to about 10-15mph at which point I shifted into drive- it ran just fine. Pulled up to a stop... no stall. It didn't stall again until I tried turning around about 2 miles after the first time it stalled. This time, I started it in neutral and pressed the overdrive button to turn O/D off. I shifted to drive and it didn''t stall. I then headed for home (after turning O/D back on) and it stalled turning into my driveway. I put it in neutral, pressed the O/D button again, but this time it stalled in drive. I had to refire, shift into 2 and get moving before I could get it in drive again.

Hopefully that provides some insight to my problem.

Thanks again! I hope we can get this figured out.

 

[BIGHVM]

I had a problem like that with my 99 sohc, I cleaned the iac and maf, changed the plugs and cleaned the plug leads with wd 40 to take off the grease- fine since, starts first time, idles well and runs a dream- I dont hink its more than that, the maf is to be cleeaned with a few cotton buds and acetone, read posts about it her with search- the iac is also well written about- I used carb cleaner on it and let it air dry and wd 40 to finish.......Dont let it get you down- there aint nothin we cant find an answer to here mate...serious is what it says and thats what we is!

 

[TomCat_Ford]

I had a problem like that with my 99 sohc, I cleaned the iac and maf, changed the plugs and cleaned the plug leads with wd 40 to take off the grease- fine since, starts first time, idles well and runs a dream- I dont hink its more than that, the maf is to be cleeaned with a few cotton buds and acetone, read posts about it her with search- the iac is also well written about- I used carb cleaner on it and let it air dry and wd 40 to finish.......Dont let it get you down- there aint nothin we cant find an answer to here mate...serious is what it says and thats what we is!

The previous owner said that the IAC (Idle Air Control, correct?) was replaced not long ago. Should I check it?

After a slightly longer drive at higher speeds, it did what I would describe as "shuddering" as the idle slowly dropped off and the engine stalled. It did that both times the engine stalled on that drive. It doesn't always stall, though. For example, it didn't stall after I drove back to my house (after it stalled at the end of my driveway), stopped at the garage door, and pulled into the garage. Also, 3 times out of 4, turning overdrive off allows me to shift into drive after a stall and drive away.

Thank you for the reassuring words.

 

[marragtop]

It sounds like your problem may be shift lever postion related. Does it EVER stall in anything other than (D)rive? Also, is there excessive play in the ignition switch and/or the shift lever?

 

[wyochimneysweep]

i had a problem that after mine warmed up and it was cold out it would idle really low in drive. i cleaned the maf and iac but finally just replaced the maf and now it idles faster in cold weather. was idling at 700-800rpm in park before now it goes to 1000rpms till it warms up. only was 120 dollars and i wish i didnt wait so long to do it. i'd replace it if its over 100k miles on it instead of cleaning cuz electrics can detriote

 

[TomCat_Ford]

It sounds like your problem may be shift lever postion related. Does it EVER stall in anything other than (D)rive? Also, is there excessive play in the ignition switch and/or the shift lever?

I got it to stall in reverse once. Every other time, it wouldn't stall in anything other than D. Park, reverse, neutral, 2, and 1 work just fine. I don't notice any play that is out of the ordinary.

I'm going to drive it into town today. I need to get it registered/licensed and I need to stop by a few other places while I'm there. I'll see if the longer drive changes anything.

EDIT: My father was talking to someone today. They had a Bronco that had similar issues. Could it be the Idle Speed Sensor? The buddy he talked to said that solved his problem.

 

[TomCat_Ford]

I was able to drive it around town without it stalling by shifting into 2 and 1 and avoiding D when approaching a stop. The only time it stalled was at the gas station. It stalled after I put it in drive to leave the pump. So this problem occurs after a fresh restart too (after I shut it off and the vehicle sat while I put 15 gallons of fuel in it and went in and paid). Hmm...

 

[96eb96]

I'm going to try another guess. I remember reading someone a while back had an issue with stalling in Drive. You say symptoms are gear dependent. There were definately issues with wiring to the trans getting shorted out, etc. Could this be an intermittant torque converter lockup? Check the wiring that goes to the trans, maybe reseat the connectors. There were issues with trans harnesses melting over the cat converters.

 

[my98nnj]

If the TC was indeed failing or locked, any gear would cause an immediate engine stop as it slamed into gear.

I would go over basic engine control signals, MAF, Crank Sensor, TPS, Fuel Pressure ect.

 

[TomCat_Ford]

Is the mass airflow sensor on my 4.0 SOHC the same as the one that is used on the regular 4.0 engine? How about the IAC?

Thanks.

 

[ZO6_Vette]

To me it sounds like the converter clutch is not unlocking on deceleration.
I am new to Explorers but the TPS or speed sensor could be giving a bad signal.
Drive the car on a flat smooth road at highway speed without changing your right foot position on the throttle, with your left foot slightly touch the brake pedal just enough to fire the brake lights but not enough to engage the brakes and see if there is an increase in engine RPM indicating the clutch has unlocked.

 

[TomCat_Ford]

It's definitely not the IAC. That looks brand new, inside and out.

How do I get the MAF off? It looks like I need a special tool? It's not just a torquz bit... there's a nipple/pin in the center of the screw head preventing my torquz bits from fitting.

It doesn't have anything to do with deceleration, as it stalled on me at the gas station the other day after the car had been shut off while I fueled it up.

Thanks for the thoughts so far. Now, if this is a computer related issue (the computer sensing something is wrong and killing the engine), wouldn't the computer have a fault code? If so, I could just take it to a local Auto Zone (they do free scans if I recall correctly) and get the code read?

EDIT: Well I was able to get to the sensor coils with a cue tip without having to remove the MAF assembly. That said, the coils looked nice and clean.

 

[96eb96]

It's definitely not the IAC. That looks brand new, inside and out.

How do I get the MAF off? It looks like I need a special tool? It's not just a torquz bit... there's a nipple/pin in the center of the screw head preventing my torquz bits from fitting.

It doesn't have anything to do with deceleration, as it stalled on me at the gas station the other day after the car had been shut off while I fueled it up.

Thanks for the thoughts so far. Now, if this is a computer related issue (the computer sensing something is wrong and killing the engine), wouldn't the computer have a fault code? If so, I could just take it to a local Auto Zone (they do free scans if I recall correctly) and get the code read?

EDIT: Well I was able to get to the sensor coils with a cue tip without having to remove the MAF assembly. That said, the coils looked nice and clean.

security torx bit for the MAF. You can get that in an auto store, sears, harbor freight etc.

 

[TomCat_Ford]

New symptom. I got it hiccup today in 2. I went into town a couple of hours ago to pick up some new wiper blades, to test the cleaned MAF (I did unhook the battery for 10+ minutes), and to just go out for a drive. I was coming up to a stop light (downhill) in 2 and the RPM's started to drop... around 400-500rpms... at which point I gave it a little throttle, and it came back. I was able to prevent the stall, but it would have stalled had I not gave it some throttle.

Thoughts? It still has yet to stall or even studder in 1, reverse, neutral, or park.

 

[TomCat_Ford]

Anyone have anymore input?

Thanks.

 

[RockyMtnHigh]

Could be a faulty fuel shut-off inertia switch, considering it happens after braking and then wont fire again. Just a thought...

 

[TomCat_Ford]

It fires back up after it stalls. I just put it in park or neutral and it fires up instantly.

 

[my98nnj]

Maybe the EGR valve is sticking open. That would indeed cause a stall upon return to idle.
The valve is only going to open at crusing speeds/RPM's.
Try disconnecting the actuator line to the valve and driving around a bit.
You're going to get a check engine light, but that can be cleared later on.

 

[mikepier]

Could possibly be the fuelpump relay? Swap it out with the A/C relay, its the same relay. It's in the fusepanel on drivers side fender area.