My '02 F-150 4.6L with 211k miles on it started missing real bad the other day. I changed the fuel filter, removed and cleaned the throttle body, egr ports and IAC valve and changed the pcv valve. Now it has a little miss at idle but the real problem is when I get into the gas hard, it misses and stutters bad! Any idea what that could be?

 

How many miles on the plugs, coil packs and wires? Or cop's? Is the CEL light on?
99% of the time your misfires are a result of a fouled plug, failed ignition source or lack of fuel.

 

CEL was on prior to recent work. 171/174 and an egr code(don't remember the number). Plugs were changed about 12k miles ago. Plug wires are original and COPs are original.

 

If the C.O.P's are originals, one or more is f-d. That being the case, I'd replace all of them. I had a VERY similar prob, it was the #3 again.

 

Wouldn't it be giving a code again if one is bad?

 

It has plug wires, and COPs? What kind of plugs did you install when they were changed?

 

No wires just coil on plugs. Ford Motorcraft plugs were put it.

 

were the plugs gapped to spec.?

 

Nope, the 2 times mine did it, never a code. The wife's Explorer did but I forced it out on the freeway with a code reader in hand. When mine did it, the one in question was visually obvious.

 

Yep, plugs were properly gapped.

Is it a must to go back with Ford cops or are the aftermarkets just as good?

 

MAF... Mass Air Flow Sensor. Try looking into that.

 

It looked a little dirty and I cleaned it off with electrical contact spray. The wire does not appear to be damaged.

 

So.......that's it??? That's all the advice I'm going to get on here?

 

Check the boots on the cops for cracks/tears/holes. Also check the plug wells for moisture, and make sure the connectors on the cops are all in tight.

 

With a post like that..............maybe.