2003 F-150 with slight misfire at idle

[AKguy]

Yea, I hate throwing money at **** that doesn't fix the problem. It was past due for spark plugs anyway, so that's really why I changed the plugs and the bad coil pack.

It's more of an annoyance than anything. The truck, drives, accelerates, blah blah like it should.

I've noticed the misfire happens intermittently. Like if I'm at idle for more than 60 seconds at a stop light, particularly in colder weather. But if I tap the gas ever so slightly, it goes away at around 800-850 rpm.

 

[insulinboy]

It's hard to troubleshoot something that isn't giving you a fault. If you suspect the egr valve and it's not to expensive I would say change it. If that doesn't fix your problem I wouldn't continue to throw money at it. Either drive it as is until it gives you a code or take it to a shop.
Maybe a f-150 forum? Someone else may have had this problem.

This.. If the truck that new has a constant misfire it would give you a code.. It should give you a code on a single misfire, but your light might not be on. Go to advanced or autozone and they will plug it up for free and see if it is in fact throwing a code, or find somebody on here like me that has a code scanner in their tool box (I used to work in a shop) By any chance is your AC on? or the Defroster (which will run the AC compressor)? I ask because when the compressor on my colorado started going bad it made the truck feel like it had a miss when in fact it was just the compressor getting tight and not wanting to run. Wouldn't throw any codes so it didn't bother me and then one day I noticed it only did it when the air was on.. Changed the compressor and it went away. Vacuum leak is another very likely culprit though that wont throw a code until its really bad

 

[AKguy]

It happens with or without the AC/defrost being on.

 

[sniper22]

Yea, I hate throwing money at **** that doesn't fix the problem. It was past due for spark plugs anyway, so that's really why I changed the plugs and the bad coil pack.

It's more of an annoyance than anything. The truck, drives, accelerates, blah blah like it should.

I've noticed the misfire happens intermittently. Like if I'm at idle for more than 60 seconds at a stop light, particularly in colder weather. But if I tap the gas ever so slightly, it goes away at around 800-850 rpm.

Drive it up here and I'll point out the culprit. I've made a lot of money off of ford owners over vacuum leaks.
It's possible that you have a bad tps but the vacuum system don't cost anything to test.

 

[AKguy]

Drive it up here and I'll point out the culprit. I've made a lot of money off of ford owners over vacuum leaks.
It's possible that you have a bad tps but the vacuum system don't cost anything to test.

That's a haul for me. But I may PM you on it.

 

[sniper22]

Thats fine. I'm usually up late and awake early.

 

[bigt61]

Find a steep hill and put the pedal to the floor. Load it down while going up. I had 2 fords a 99 and 01 and whenever I felt like I had a miss I did exactly that. Every time it set the engine light off on misfire and told me which coil pack was bad.

I tried everything under the sun, then tried that and it always worked.

 

[safellows1967]

Check the Idle Air Control Solenoid valve.

 

[woodstock]

If this has a throttlebody did you clean the butterfly? They will get crap on the edge of it and the body itself and is most noticeable at idle. and I do run injector cleaner through my fuel 4 times a year.

 

[Realstudent368]

I had a problem with mine turned out to be soot buildup in the intake/aircleaner tube...