Engine stalls while driving why?

How long since a tune-up? Check fuel pressure. If no pressure release on this system, you can also check to see if fuel pressure drops like rock, with everything off, if it does, you have a pressure leak.

This guide can help us fix it

https://www.2carpros.com/articles/engine-stalls

Usually with idle issues, you look for a leak of some kind, fuel--vacuum--egr, something of that nature. Also, check your idle air system.

Just to add, the gas smell could come from evap system? Check the fuel pressure regulator vacuum line, if gas in the line, regulator is faulty.

1991 Ford Explorer 6 cyl Two Wheel Drive Automatic

My explorer won't stay running when cold and bogs down while driving and giving alot of gas. The check engine light comes on and off.

CEL On, pull the code/s from the computer and comeback with it -we start here

I got 172, ho2s lean, 543, secondary fuel pump fault and 556, primary fuel pump fault

Engine Mechanical problem
1991 Ford Explorer 6 cyl Two Wheel Drive Automatic 230 K miles

Long block recently installed (6 mo.) by Thunderbolt in Houston. Runs great, however, two days ago, after driving for about an hour, vehicle was parked. A couple of hours later, vehicle would turn over, but not start. The next day, engine started and ran smoothly for about 20 minutes and then the engine shut off as you would normally turn it off. About an hour later, engine started up and ran smoothly for about 15-20 minutes and then it stopped running as if shut off. I changed the fuel filter with same issue. I suspect the fuel relay or the inertia switch/wiring. Fuel pump is original, but seems to be working fine. 230,000 miles on frame.

If the check engine light hasn't come on, I would start by checking fuel pump pressure. It could be running but not producing. Here is a how to for checking. Watch the video. Also, you will need a gauge. Most parts stores will lend or rent them to you.

https://www.2carpros.com/how_to/how_to_check_fuel_pressure.htm

Let me know what you find.

Joe

What would cause the truck to stop running all of a sudden, check engine light came on aftering stopping at a stop sign and then when i went to give it gas to go it just stopped and cut off. It still has battery power, no other lights came on except for the ones that come on when you first start the vehicle. Does it have something to do with the fuel injection, or pump.

you did not post the kind of car and engine. but posibly the ignition control module went out or even fuel pump.have someone listen under truck near gas tank for fuel pump buzzing if so then fuel pump is ok.if no noise at all then possibly pump is bad.

This turned out to be the ECT [Engine Coolant Temperature] sensor, according to my Ford dealer service department which was reading -20 on a 40 degree day. For those of you experienced enough how long should it take to diagnose this? What is a fair charge in diagnostic hours? Also, how long would it take to fix? According to the Haynes manual you have to remove the upper intake manifold, but it also states that it might be accessible if the thermostat housing is removed. If this is the case, shouldn’t this be an easy repair? It will start ok, idle high for 20 sec and then stall. Once it stalls it will not start up easily again - just cranks and cranks. If I hold the pedal all the way down I can get it to start very rough and then I have to keep the idle up or it will stall. Once forced into gear it will not stall and has all the power I ask it for. But it idles too high and surges while slowing down around 20 MPH. I can rule out the IAC and MAF and EGR valve. It will always start right away after resting over night. Surge also happens in neutral idle when you pulse the trottle. It revs up and hangs there too long before slowing down again. It will also stall when I take it out of gear. It will rev up and then fall to a stall. There are no OBDII codes returned. By the way this all began rather suddenly – drove 10 miles to store one day, went in, came out, started car fine, it stalled, then would not easily start again – before which you would not know anything was wrong. Any Ideas?

Things I think it is not and why:
- Fuel pump - it never loses power once in gear.
- IAC - I tryed a new one
- MAF - I tryed a new one
- EGR - took it out tested valve and blocked pipe while running with no change.
- Vac Leak - because it is so hard to restart?

Things I think it might be and why:
- Vac Leak - high idle : no symtoms during open throttle.
- O2 sensor - I do not know if there were codes for the O2 because now the OBDII for O2 is not ready because I disconnected the battery. I believe however that there were no codes when the O2 was ready

Comments very welcome!

[quote:e576422fc5="99expsohc"]I have a 1999 Ford Explorer 6 cyl SOHC - It will start ok, idle high for 20 sec and then stall. Once it stalls it will not start up easily again - just cranks and cranks. If I hold the pedal all the way down I can get it to start very rough and then I have to keep the idle up or it will stall. I have replaced the Idle Air Control valve but it did not help – I didn’t really expect it to. It will start right away and run ok, if started for the first time after resting. It runs a little high idle in gear and will surge when slowing down and shifting around 5 - 10 MPH – does not accelerate the vehicle though and seems as though it might be at the downshift - surge also happens in neutral idle when you pulse the trottle. It might be fine going around the block, but if I put it out of gear and then back in gear it could easily stall as soon as I do so unless I compensate with the trottle before switching. There are no OBDII codes returned. The MAF seems to operate ok using a voltmeter but I have not replaced it yet. By the way this all began rather suddenly – drove 10 miles to store one day, went in, came out, started car fine, it stalled, then would not easily start again – before which you would not know anything was wrong. Any Ideas?[/quote:e576422fc5]

Hey 99,
If your not getting any codes, then its a tough call on my end! I'm sure if you were able to view data stream on a scanner it would reveal a direction to go in. I'm assuming you don't have a scanner. Though those MAF's are a known issue, I'm reluctant to say change it as they are pretty pricey. I gotta recommend taking it to a trusted shop for an accurate diagnosis. Unless you can get me some data stream values that is. Sorry

Chris

Just a couple notes to add. Disconnecting the battery to clear the codes will further complicate rather than help. I don't see a correlation between the OBDII monitors and the O2. Also, I have run into bad MAF sensor that were "new". Actually they are usually remanufactured. May want to consider the dealer part on that one. DPFE sensors are also common on these.

it has run great. While driving under normal conditions the engine just shuts off, all other items contiune to work electric A/C ect. It almost as if there is no gas in the car. The engine will turn over but just wont start, after a few minutes the engine will start and drive again, but after a few more minutes of driving it will die again. Its a never ending cycle, runs, dies, works again after a few minutes, dies again. It does this when coasting, at a full stop, accelerating stopping, not at any particular time. All guages are in line, gas, elec, oil, I cant seem to find the problem. Any ideas?

Sounds electrical to me.Check for spark at the plug(be sure to ground plug).If no spark,be sure the fuel pumps kick in when you turn the key to the "on" position. If the fuel pumps don't click on, check the relay. If relay ok,and fuel is reaching the fuel rail, then I would guess the problem is in the primary electrical circuit to the ignition. Could be a coil cutting out,or ignition system problems such as stator, or losing PIP signal. Have the codes scanned for a lead.

My 1998 Ford Explorer sometimes stalls at stop signs or when pulling into a parking spot. It usually starts right back up again. When I had trouble getting it to stay started, it worked better in reverse. I had the fuel filter replaced and new spark plugs put in. I changed the air filter and cleaned the air sensor. It seems to stall less often when the fuel tank in near fuel. The SUV will stall once or twice and then not again for 2-3 days.

If you are still having the problem, try replacing the electronic engine control relay. it is under the hood and costs about $5. This happend to me but there were no consistancies about when or what conditions it happened.

My truck is stalling when braking. I can drive the truck fine once it is started as long as i keep the accelerator pushed at the same time I am breaking. Sometimes it is so hard to start and other times it runs fine. We have replaced the throttle control and that helped for a while. I drove this car to Florida and it was fine all the way there. When I went to drive it the day after we arrived it stalled. I put some Fuel system cleaner in it and didn't have another problem and drove it all the way back to Indiana. It is 2 weeks later and it is stalling again.

Try unplugging the MAF on the air intake plenum, near the air filter box, see if it smoothes out. If it does you can try cleaning it with a Q-Tip and alcohol. or replace it!

This truck is important to me b/c it is my only mode of transportation since I am in graduate school.

I routinely maintain this vehicle, but today the truck started like normal, idle raised twice, then just slowly stumbled and died. I tried to restart but it would not turnover. I tried it on and off and nothing. Finally it went and did the same thing. After fussing with it, I finally got it to go and it drove fine.

The battery, starter are good, I even tried to replace the ignition coil...but that was fine.

No idea. Makes no sense unless it is a sensor, but there is no way to check b/c it has no computer hookup.

How do I solve this? What could it be?
Thanks.

Graduate school huh? Better check the spelling on your signature :lol:

Try cleaning the MAF, may not be it but a good start.

Many Explorer owners have experienced "bogging" or "missing" or just unsteady performance in their 4.0 engine and have been frustrated by lots of expensive "non-fixes". Ford has these problems more than other makes and the 4.0 engine seems to be more susceptible to the problem than other Ford engines.

It seems that a "missing" engine culprit is actually the computer's sensor inside the Mass Air Flow Sensor (MAF). It eventually just gets a little dirty or builds up its own patina in the filament wires. A dirty or slightly patinated filament will send the wrong air reading to the computer, saying it is getting more air than it really is and the computer will tell the EFI to send in the wrong mix of fuel, thus, the bogging. The patina seems to form faster if you live in a damp climate. If you have had bogging or missing or idle spots, about every 25K miles plan on this quick cleaning job:
When your engine is cool, remove the wiring clip from the side of the black plastic sensor part of the MAF aluminum body. To remove the MAF interior sensor wire, you will need a Security Star (Size T15 or T20) screwdriver or screwdriver bit for a power screwdriver. Remove the two security star-head screws and carefully remove the sensor. You will see the two sensor filaments…they look almost like the filaments on a light bulb. Carefully spray the filaments with an O2 safe carburetor cleaner, such as Gumout. Let it dry thoroughly. I help mine along with a careful blast or two of canned dry air. While it is drying carefully wipe the aluminum mount surface of the MAF body if there is any dust there, but be careful not to get dust in the mount hole. When the sensor is dry, replace the sensor back in the MAF body and secure with the security star-head screws. These don't need to be torqued down, just simply hand tight. Replace the wiring clip. Then start up your engine.

Service Writer,

Thanks for proofreading...I did it quick, but the signature is changed...thanks for your sharpness.

I will clean the MAF sensor and see.

Do you think that it could be the Idle Air Bypass Controller?

If so, is it possible to clean?

Thanks.

Yes it could, have a gasket on hand when you do it.

Service Writer,

Thanks for the reply.

Is the IAB difficult to take apart? Is there anything I should look out for?

Thanks.

vacuum leak.check vacuum tree at rear drivers side if intake manifold for soft or disconnected lines

Thanks for all the info.
It is just weird that it has been fine since.

I will clean them tomorrow and let you know.

THanks again.

It knew you contacted us! 8)

Guys,

thanks a ton for the advice, but not a problem since I posted. unfortunately I was unable to clean the MAF and Bypass, but is on my list soon.

Thanks again for all the advice and support,
Franchise

Probably a piece of carbon that finally worked free.

Just a thought. I had an issue with my 1993 explorer where the engine would just die. There didn't seem to be any consistancy in when it died or any cause. It turned out to be the electronic engine control relay. It is a small box relay under the hood and it was about $4 back then.