Rough/ low idle and sluggish accleration.

[hctim89]

I have a 99 ford explorer xlt 4 door. Well to start off this problem my truck had a really bad time all of the sudden keeping at around 800 rpms ideling speed it would drop till it staled out and id have to keep on the accekerator at all times to not stall out. we changed the iac and the tps and it helped for a little while. now its ideling but it will idle at like 500rpms and sometimes drop down worse when i come to a stop and let off the acclerator but if i stay stopped for a few seconds itll start to rise back to 500 rpms. also when i give it gas from start the car shakes a little the engine sounds likes its missing and its sluggish and doesnt want to git up and go not that a ford explorer ever has but its way past normal. Any ideas maybe the maf or vacum lines o have no idea. ohh im running seafoam motor treatment throiugh the gas tank and crankcase to see if that helps. ohhhh ye the mpg dropped all the way down to a whopping 10ish miles to the gallon. thank god gas is expensive right??

 

[RedEB]

I have a 99 ford explorer xlt 4 door. Well to start off this problem my truck had a really bad time all of the sudden keeping at around 800 rpms ideling speed it would drop till it staled out and id have to keep on the accekerator at all times to not stall out. we changed the iac and the tps and it helped for a little while. now its ideling but it will idle at like 500rpms and sometimes drop down worse when i come to a stop and let off the acclerator but if i stay stopped for a few seconds itll start to rise back to 500 rpms. also when i give it gas from start the car shakes a little the engine sounds likes its missing and its sluggish and doesnt want to git up and go not that a ford explorer ever has but its way past normal. Any ideas maybe the maf or vacum lines o have no idea. ohh im running seafoam motor treatment throiugh the gas tank and crankcase to see if that helps. ohhhh ye the mpg dropped all the way down to a whopping 10ish miles to the gallon. thank god gas is expensive right??

My first question would be what motor do you have?? V6 OHV, SOHC or V8?? Have you checked out the spark plugs?? If not, it might not be a bad idea to do a full tune up with new wires, plugs, change oil/filter and air filter. By your description, however, it almost sounds like you have a vacuum leak somewhere. I know the SOHCs have a bad tendency to blow O-rings and that can produce similar symptoms to what you are describing.
Do you hear any air rushing sounds???

 

[RedEB]

Oh, just another thought. Have you replaced the fuel filter recently??? Sometimes clogged fuel filters can cause those types of problems...

 

[JohnJ]

This sounds like a classic massive leak between the MAF and TB.

 

[hctim89]

umm dont quote me but im pretty sure its a ohv but positive on the v6 part and no havent changed the fuel filter lately.

 

[hctim89]

My first question would be what motor do you have?? V6 OHV, SOHC or V8?? Have you checked out the spark plugs?? If not, it might not be a bad idea to do a full tune up with new wires, plugs, change oil/filter and air filter. By your description, however, it almost sounds like you have a vacuum leak somewhere. I know the SOHCs have a bad tendency to blow O-rings and that can produce similar symptoms to what you are describing.
Do you hear any air rushing sounds???

umm dont quote me but im pretty sure its a ohv but positive on the v6 part and no havent changed the fuel filter lately. and as far as the air rushing sounds i have no clue cause im usually in the truck and the rear end hums like a ***** cause it needs fixed too or something

 

[RedEB]

umm dont quote me but im pretty sure its a ohv but positive on the v6 part and no havent changed the fuel filter lately. and as far as the air rushing sounds i have no clue cause im usually in the truck and the rear end hums like a ***** cause it needs fixed too or something

OHVs are great engines, you're lucky you don't have the timing chain mumbo jumbo!- I'm having to mess with that right now...
I know OHVs have had a problem with lower intake gasket leaks, one suggestion I have is to go buy some starter fluid and spray it around the lower intake where it mates with the engine block. See if the RPMs surge or change as you spray as that will indicate a vacuum leak, which I suspect this may be. You might want to change the fuel filter as that is an easy and cheap possible fix to your solution. The intake gaskets are likewise easy, but a little more time consuming...
Good luck and let us know what you find.

 

[aldive]

Have you scanned to be sure the open loop/closed loop switching is functioning. Also have you determined the O2 sensor function?

 

[RedEB]

^^^^^^^
Great point. Are you getting a CEL or fault code?

 

[jtmx101]

Im having the same problem in my 2000, When it is cold, it idles real rough, and refuses to accelerate, but it only does it about halfway down the street out of my neighborhood in the mourning, and then runs fine, the coolant is circulating fine. I think it is eather a clogged fuel filter or a vaccume leak. any ideas??