Explorer stalls only when hot??

[poole]

I have 2000 for explorer 4wd 4.0L SOHC with 177k.. Whenever the temp is above about 60 degrees (f) and the vehicle is run for more than about 2.5 hours, it will start to stall whenever the engine is not under a load. If I try to maintain speed or let off to slow down, the rpms will bottom out, the oil pressure guage bottoms out, then it revs back up. Sometimes it will completely stall. The only way I can get it moving again is to keep the rpms up and catch it just right so that it stays under a load. This problem started at the end of last summer and resolved in the winter months and is now back with warmer weather.

I put a fuel pressure gauge on it while the problem was occurring and the fuel pressure was also dropping to almost nothing when the rpms get low. I am not very educated on fuel pumps and am not sure if that is normal when the rpms get low or not. The fuel pump also "whines" when this problem starts. That makes me think it is probably the fuel pump, but I have not talked to many people who are familiar with this type of behavior for a fuel pump.

So Im open to suggestions for any other possibilities before I replace the fuel pump. The IAC, fuel filter, plugs and plug wires have been replaced. The injectors and throttle body have also been cleaned.

Thanks for the suggestions!!

 

[poole]

I also replaced the intake gaskets last year while this problem was occuring, it did not improve.

 

[Rarestace]

it does sound like its the pump if the pressure drops when its about to stall is there anyway you can measure the voltage to the pump when its about to stall to see if maybe its an electrical problem cutting power to the pump.

 

[poole]

it does sound like its the pump if the pressure drops when its about to stall is there anyway you can measure the voltage to the pump when its about to stall to see if maybe its an electrical problem cutting power to the pump.

Any idea where the easiest place would be for me to get a volt meter on those wires would be? I do know that the relay is really hot when all of this is going on.

 

[lounge lizard]

lately there has been a rash of cats failing and getting plugged up.

might be worth a shot!

 

[RomeovilleIL]

I think the operative signal is the whining sound when the pressure drops off. Electrical issues would likely cause the pump to stop intermitently or maybe slow down, but would not expect that behavior to make noise.

Pump is likely going south. When engine is hot and whether is warm the pump is getting more stress from vaporlocking/bogging down. Plenty of threads on how to replace. I've done the tank drop a couple times - isn't really that bad as long as you have less than 1/4 tank. Lots of folks have good results with cutting an access panel - check the stickys.

 

[kotz]

check the vacum lines, it sounds like thats your problum.

 

[poole]

check the vacum lines, it sounds like thats your problum.

So far I have not been able to find any leaks.....not to say that its not there....just haven't had any luck finding any yet.

 

[poole]

Could not find any vacuum leaks today. Cleaned the MAF sensor and the throttle body just for fun....still not fixed.

I read another thread with a similar problem. The OP said fresh cool gas would temporarily alleviate the problem. I remember last year on several occasions filling up when the problem was occurring and it did clear up for a short while. That would lead me to think it is in fact the fuel pump....fuel pump gets hot, starts to fail....filling up with cooler fuel cools pump just enough to temporarily work again. My only other concern is the fact that the last 2 fuel filters were pretty nasty. Im wondering if the pump is getting hot because it is trying to overcome an obstruction or if its just going bad in general. Im thinking about just going with the pump and see what happens.

 

[kotz]

If the filters get dirty fast you might have a lot of crap in the tank itself causing the pump to be over worked and get hot, maybe cause a partialy plugged filter as well. I have found out that your first guess is normily the problem. sometimes you just have to go with your gut. it sounds to me like its a fuel or air problem. I had to drive with the gas cap off on my first ex because it wasent venting good. have you tryed a new cap?

 

[acchan]

Anyone know what the problem ended up being? My '00 4.0 ohv is doing the exact same thing. I'd really like to fix it.

 

[matt351]

Mine too...