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2000 F150 4.6l

1.8K views 3 replies 4 participants last post by  bassman97  
#1 ·
:(Hello, wondering if anyone would know the reason for my truck running rough when accelerating. The Engine light came on and I replaced the IAC. (had problems with winter starting) The engine light has come off however the truck is still running rough at acceleration. I started the truck and unplugged the Mass Air Sensor and the truck did not change-is this a pretty good indication that the MAS is not working?
 
#2 ·
Ours does it when one of the plugs needs cleaned. But ours is a 5.4 and one specific cylinder gums up the plug. But it acts like half the plugs aren't firing just from that one malfunctioning one.

Probably something else with yours but it's one possibility.

As for the Mass, sure sounds like it's not if it doesn't know when you have it unplugged or not. How's the air filter?
 
#3 ·
they have a beatup old aerostar at work for a shop truck, it was having all kinds of rough running issues...my buddy had the airbox off of it, and just walking by I noticed you could see daylight inside- the air filter was not sitting in the box right, and it was sucking air around it...put the filter back in right and it ran like a top...he was a little upset that was all it was...the MAF on those older ones apparently dont like turbulent air coming in anyway but straight into the duct?
 
#4 ·
That's right, which is why the CAIs for Mustangs w/ the elbow in front of the MAF can cause problems.

As for the topic of this discussion, try cleaning it w/ rubbing alcohol and a Q-tip (just be gentle as the sensor is very delicate) and see if that helps. If not, try the plugs.