Hesitation

[hoffyinaz]

First hello to all, I am finally asking my first advice.
I have a 99 Mercury Mountaineer with the V6 4.0 (I believe its 4.0). Anyways whenever I get on it, it always hesitates and kinda burps before taking off. I have replaced air filter, cleaned TB, changed plugs and done a fuel system flush. What else could I check?????
Thanks for any advice.

 

[Jason_25]

How is the idle? How many miles? Have you replaced the plugs and wires? That's what I would try if you're at 50K miles or more.

 

[hoffyinaz]

Sorry the idle is fine, its at 80K miles. I've changed plugs not wires. Would you recommend the wires, what about distributor and coil. Any brands recommended???????

 

[TPLYNCH]

Change wires, no distributor, coils possible but not likely. Clean MAS and Throttle Body. May also need to tighten the throttle cable itself too.

 

[Runnin'OnEmpty]

If cleaning the MAS dosen't help, then suspect the TPS being bad. They do wear out, and 80K is enough miles for it to have developed a flat spot.

Like tplynch says, it's probably dirty MAS wires.....

 

[hoffyinaz]

I tried a search for MAS and find nothing, what does MAS and TPS stand for. Is there a write-up on how to clean MAS or is it an easy wash it and put back.

 

[hoffyinaz]

I tried a search for MAS and find nothing, what does MAS and TPS stand for. Is there a write-up on how to clean MAS or is it an easy wash it and put back.

Mass Airflow ????

Trottle Position ??

 

[tomblin1]

TPS = Throttle Position Sensor

MAS = Mass Airflow Sensor

There is a good post about cleaning the Mass Airflow
Sensor. Try a search. Wires will wear out over time. If you can replace plugs then wires are easy. Just make sure you hook up the wires in the same way as they were before, otherwise you will mess up your timing.
Wires start at about $40 at autoparts stores.

 

[TPLYNCH]

Look in the Usefull Threads section. I think this is posted there... http://www.explorerforum.com/forums/showthread.php?threadid=56770&perpage=25&pagenumber=1