05 4.0 throttle issue

[Randy]

Recently the car has been acting up when I accelerate from a stop. It will hesitate for a half second or so and then surge forward like I had given it more gas than I actually did. Only thing done is a bama tune (race currently) (but it does it on street tune as well) BBk cai, gms coil pack, Taylor street thunder wires, factory spec plugs and gapped appropriately. That's all for performance. Any idea as to what this could be? Could it be the tune? I have had the tune and all other mods for about a year. Just started acting up about 2 months ago.

 

[Lightningtruck]

Is this only under very light throttle? Mine is a bit touchy off-idle at light throttle coming from a stop. I haven't checked it yet. My truck (04 F150 5.4L 3V) was also like that when my throttle body needed cleaning. Carbon around the throttle plate made it hard for the electronic throttle control to control it. Just a thought. I'm interested to hear what you find.

 

[Ray721]

Throttle body might be dirty and MAF sensor might be dirty as well. The CAI has more flow and more dirt probably gets by.

I've had similar issues with my GT and cleaning up those things helped.

 

[Randy]

Thanks guys, ill check those today. And yes it is only under light throttle.

 

[TexasBlownV8]

+1, clean the maf and tb first.
Also, when were the spark plugs changed last?

 

[Randy]

Same time installed the coil pack and wires. About a year ago. And I don't even think I put the usual 12-15k on it since then. Was parked all winter and I live in a small town now, so I walk everywhere.

 

[TexasBlownV8]

I only mention plugs because, even though the stock plugs are "supposed" to be good for 100k miles, they tend to wear on the driver side, causing running and idling issues.

But, clean the maf (using maf cleaner) and make sure the TB is clean (from the back side, you may need to remove it).

I recently ran into the same symptoms on another v6, and fixed them by cleaning maf and tb and replacing the stock spark plugs.

 

[Lightningtruck]

Randy: Just curious if you have checked this out yet? If it ever quits raining here I am going to pull the TB on mine and give it a good cleaning and see if that helps. I'm pretty sure it will.

Thanks,

 

[Lightningtruck]

Mike,
Just curious, do you know why the plugs "wear on the driver side"? Never heard that before, and was wondering if you knew why.

Thanks,

 

[TexasBlownV8]

Well, the last set I pulled, the part numbers on the plugs were slightly different on each side of the motor. I've only seen this be real bad on the stock plugs, where the center electrodes were rounded almost to a point like on a pencil! Then the ones on the passenger side look close to new. That's after 30-40k miles, or even less (the stockers on my '05 were like that after about 25k miles, started missing out a little here and there, idling a little rough at times, etc.).

If the plugs are otherwise the same (electrically and heat-range), the wires to the drive side plugs are shorter than the ones to the passenger side, hence less resistance and a possible hotter spark.

 

[Lightningtruck]

Wow, that's pretty wild stuff. I never would have thought it. But will keep an eye out now. I think I put all of the same Autolites in mine when I swapped the new engine in.

Thanks!

 

[Randy]

Just had time to check it out between work and school. Took her off and OMFG she was dirty as fuck. The throttle plate was bronzed and the tb around it was fucking black. Is this normal? Took it for a ride and she seemed fine. Didn't have maf cleaner on hand so ill do that sometime soon.

 

[Lightningtruck]

Yeah, you gotta clean 'em out when they get like that or they get to acting weird. My truck is doing it again, LOL.

 

[Randy]

Ok cool. As bad as it was, it had me a
Little worried Lol.