1999 mountaineer 4.0l sohc

[mountaineer99]

I have a 1999 mountaineer with 4.0l v6 the problem that I am having is that the engine run but if I give it any throttle it wants to die out. If I pump the gas pedal I can get it to reach 3000 rpm. If I take my foot off the gas it seems to idle. THe truck was running fine and this problem occurred with no warning.
I replaced the spark plugs and wires first and it made no difference. I then took the coil pack off and checked the resistance and it checked out good. I checked the throttle position sensor and it checked good but I replaced it anyway. I replaced the gas filter. I thought it was the fuel pressure regulator which is part of the fuel pump assembly so I replaced the fuel pump.
I still have the same problem.
Could I have a bad fuel injector?
What about the electronic control module?
I do not have engine light on. I did have a engine light on several months ago which was a vacuum leak I believe the code was p0445 but the light went off when I replaced the gas cap.
I out of suggestions I do not know what to try to replace next.

 

[joker1457]

Check all your connections the mass air flow sensor and map sensor, they both will let the engine run but not well if the connection is bad. Are you getting any chaeck engine lights at all?

 

[mountaineer99]

I have no check engine light on.
Where is the map sensor located?
Is there a way to test the fuel injectors?

 

[joker1457]

My apologies I guess the SOHC doesnt us a map sensor, The Mass Air flow sensor is located on the air box (top Side) as fare as the fuel injectors you would have to tear down the top of the engine to pull them chances are pretty high they are fine. I would run a fuel injection cleaner through if you are concerned.

 

[mountaineer99]

I removed the egr valve and made sure it was working. I then inspected the mass air flow sensor and discovered that a dead fly was on the small wireof one of the probes I took the fly off and I sprayed carb cleaner on the probes.
I then started the the truck and it is now running fine. I drove it around and after a half hour the check engine light is now on. I will check the code and then post it.
Thanks for the help.
I spent almost $600.00 in parts to find out it is a fly!

 

[bluestream1]

I have a similar problem with a different vehicle, and it turned out to have a few bad fuel injectors. Have you checked the fuel pump pressure?

 

[mountaineer99]

1999 mountaineer 4.0l

I have the truck running now but I started driving today and the check engine light is flashing. The vehicle does get up to highway speed but the accelleration is bad and now it seems to be idling funny.
I am going to find somewhere to check the code on but I have never seen the check engine light flash like that.

 

[joker1457]

Chances are very high because you disconnected the Mass air flow Sensor it sent a code to the computer if you can get it into some place and have it reset the car should be just fine. I had the same thing happen to me when I put a cold air intake on my Stratus R/T a couple of years ago.

 

[mountaineer99]

engine light on p0171 and p0174

My engine light has stayed on I disconnected the battery and cleared the light the light came on after a day. The codes are p171 and p174 which points to the mass air flow sensor. Is there a way to test it I replaced it about two years ago. I not sure if I screwed it up by spraying it with carb cleaner.
The new fuel pump assembly I installed is causing the gas gauge tonot work the gauge is always reading full now. Do you think it is a problem with the float?