My car hiccups/hesitates when taking off from a stop

[bigROC 5.0]

It idles very smooth and once it gets going it runs really smooth as well. The only issue I'm having is that it sort of hiccups when I take off from a stop. I just bought this car and it wasn't acting up during the test drive. The previous owner said that it did throw a Check Engine light and the code was for the MAF sensor. He said he cleaned it and the light hasn't returned.

Do you guys think the MAF is starting to give out? Or should I look elsewhere?


2001 Mercury Mountaineer 5.0L with about 170K miles

 

[Rick]

I would see if it changes when you unplug the MAF. It should run normally, just not efficiently.

 

[bigROC 5.0]

So today I installed new plugs and wires. I also installed a new Ford MAF sensor. I cleaned the throttle body a lil bit since I had the air intake hose removed. Buttoned everything up and it fired right up when I started it. It idled rough for maybe 5 seconds but then smoothed out. I just let it sit and warm up and suddenly it died out after about 10 minutes of idling. It didn't putt out, it just cut off like the key was turned.

When I started it back up I had to give it some gas to get it going before it idled smooth again but then died out once again after idling for maybe five minutes this time. It started right back up and this time I took it for a drive and it didn't die at all. The rpms dropped low a couple times when stopping at stop sign. The same "hiccup" is there on acceleration from a stop. Doesn't happen every time just like before. I took it on a long straight away and I can feel it missing a bit which is the same as before. I put the old maf sensor back on and it runs the same, if not better from what I can tell. I had it idling again for about 30 minutes with the old maf sensor and it didn't die out.

I also unplugged the old maf sensor with the car running and the idle didn't change at all. Didn't try to drive with it unplugged. Somebody told me if nothing changes when you unplug the maf sensor then it is bad. I didn't try unplugging the new one when it was installed.

The old plugs and wires seemed to be the original motorcrafts. The gap on them were 80+. I installed Prestolite wires and Autolite platinum spark plugs. The MAF was a new Ford part. I gonna put the new maf sensor back on and see how it runs tomorrow.