Occasional hesitation/misfiring when accelerating.

[goober71]

Hi,
I have a 98 XLT V8 AWD explorer. Occasionally, when i accelerate while going on an upslope (on-ramp, small hill, etc), it seems like the truck hesitates or misfires for a little bit. If i really step on the gas hard, then the transmission downshifts and things are fine.
I tried adding a fuel injection cleaner in the gas but it didn't seem to help. Does not happen all the time, only occasionally.
Any ideas?

Goober

 

[gensic11]

check your spark plugs you may have a cylinder misfiring.. that's generally the case with your symptoms

 

[exploded99]

But also if you have never cleaned your MAF pull it out and clean it with throttle body cleaner. You can search this site and find instructions.

My 99 V8 had some starting/hesitation/missing issues that cleared up when I cleaned the MAF.

 

[jimbo74]

does you check engine light come on? the computer might be storing a misfire trouble code

 

[goober71]

Thanks for the info, guys. i will check the spark plugs and the MAF. I have never cleaned the MAF. The spark plugs were done about 8 months/7000 miles back.
The check engine light has not come on so far. Another question i had was.....would the transmission be causing this in any way? maybe lingering in overdrive instead of shifting into a lower gear?

Goober

 

[exploded99]

My AWD felt like it had a hesitation in the transmission - kind of a pause before it kicked in. But I did the following:

Cleaned MAF
Removed and cleaned the throttle body
Put two bottles of techron in a tank of gas and ran it thru
Put a can of BG44k in a HALF tank of gas and ran it thru.

Cleaning the throttle body is not hard - get a new gasket. Pull the throttle/cruise control bracket as an assembly ( 3 bolts). the cables just pop off of the little arm on the throttle body that opens the throttle plate - no need to mess with them. Then 4 bolts and the throttle body slips off. 30 minute job.

The bg 44 k is about 22.00 a can but it works. I used the techron for a "precleaning" since I had never cleaned my fuel system. Don't skip the bg44k.

Your 5.0 will have more low end power, the "hesitation" will go away, and your acceleration will be a little better.

Don't know your mileage but if you've never changed tranny or transfer case fluid you should consider it. I use mobil1 synthetic atf. Put a new filter in the tranny if you do it. There will be a lot of crap in the tranny pan. I don't recommend power flushes cause that stuff in the pan will not get cleaned out.

Good luck!

 

[goober71]

Thanks for the info, exploded!! i will definitely try out what you suggested.
Where is bg 44 available? autozone?
Also, my X has 66k miles on it. Should i try the transmission flush/fill at this mileage?

Goober.

 

[exploded99]

In Denver its NAPA or Advance auto, not autozone.

You are due for a flush and fill on the tranny and transfer case if its never been done. I think your manual says to replace tranny fluid every 36k or so.

When you do it, put it up on some ramps and drain the torque conerter. There is a plastic plug on the bottom of the bellhousing that pops out, spin your crankshaft with a 22mm (I think) socket on your front crank pulley till you see the little bolt, and remove it. You will get 2 gallons out of the torque converter, the rest out of the pan. 12 quarts total, and a filter. Clean the pan and the magnet in the pan, filter pulls out and some more fluid drains when pull the filter.

Reuse the factory gasket on the pan - its a great gasket. I use synthetic fluid cause I tow stuff now and then and the synthetics are better with pressure and heat. More expensive, but tranny rebuilds are way expensive. I change synthetic fluid every 50k.

Transfer case uses atf also, get enough for that. This is one of those messy jobs, no way around it, you will spill some fluid so don't wear your good clothes. Go easy on the transfer case filler plugs, thats an aluminum case. Snug em up, but don't try to really crank them down.

Oh yeah, you will find a small plastic plug in the tranny pan if your tranny has never been flushed. No worries, it plugs the filler hole at the factory till they fill it with fluid.

Also, forgot to mention to clean your Idle air control valve while you are doing the throttle body - its got those two bolts holding it on the throttle body.

Now if you put some plugs in you will have completed a "major" tune up.