00 XLT AWD Skipping issue.

[h3rbie]

Recently my wifes 00 5.0 XLT is skipping upon aggressive accelleration or going up hill. This only happens once the engine is warmed up, and between the speeds of 40-60 miles an hour, sometimes it happens from a dead stop when you are trying to get out into traffic. It sounds like it's a misfire when it happens.

The truck has about 120K miles on it, it's had regular maint on it since we got it with 40K miles on it. The plugs/wires were swapped out about 10 months ago. I was thinking it might be the coil pack.

Can anyone shed any light on what this could possibly be? I was going to go get the coil pack tonight and swap it out but if it's not that, there is 45 bucks I didn't need to spend on resolving the problem. Has anyone expierienced similar problems, if so what was the resolution? If any more information is needed please let me know and I will do my best to share what I know.

Thanks,

Tom

 

[exploded99]

An ignition miss due to a coil pack will usually set the CEL.

Thats a few miles, so it might be smart to clean the MAF and replace the fuel filter if that has not been done recently. Start with the easy tune up type stuff. You can find instructions on this site if you need them.

If it still misses, then you can start looking for bigger problems.

 

[h3rbie]

Ok tonight I will try cleaning the MAF and reset the computer. Hopefully it is just something as stupid as this instead of having to spend alot of money fixing it.

I will post back when I get it completed.

 

[h3rbie]

Well cleaning the MAF didn't work for my issue, it actually created a second issue. I still have the skipping as described in my first post. Now when I put the truck in Drive and go to accelerate it spits and sputters and then it finally "cleans up" and takes off like a raped ape.

Any ideas?

 

[exploded99]

Ha! Ya, the V8's tend to lose some perfomance as they get older. Then you start cleaning stuff up and all of a sudden they start running more like when they were new. Too bad it never really helps the mileage.

As far as your new sputter, make sure you got everything back together tight and don't have any vacuum leaks. Probably should check the big intake tube and make sure there are no cracks in it and make sure it is seated properly and the clamps are tight. Check your hoses for any leaks.

Since you are not getting a CEL, we are probably looking for something that is not working correctly that does not set a check engine light when it has problems.

So we have O2 sensors, fuel pump, camshaft position sensor, crankshft position sensor, throttle position sensor, or possibly a MAF that isn't working just right. Coil pack is possible, but the engine usually senses ignition misses.

All of those can cause missing under heavy acceleration. Do you want to try and diagnose this urself? Or would you consider spending 80 to 100 to have the shop diagnose it smarter?
Basically, it is a process of checking the various components till you find the culprit.

If it were my truck, I would check the fuel pump pressure after the engine is hot. See if it drops when you rev the engine up. I would start with fuel because this only seems to appear when you are doing heavy acceleration.