Car bucking?

[AzianStang]

I've noticed lately that the car's bucking a little bit especially in the lower gears... not like from slack in the drivetrain or anything, but it bucks while in gear, and I can't figure out what it is. I'd search but it's not working right now... any clues?? Is this normal?

:shrug:

 

[powersof12]

My 5.0L's would do this if water got on my K&N and mist makes it on to the MAF. Any chance moisture is in the engine bay?

 

[sweet88gt]

Vacuum leak.

Check all hoses and the intake tube to see if its properly seated.

 

[Posi]

I hate to say it because it's to easy but when is the last time the plugs were changed?

 

[AzianStang]

Vacuum leak.

Check all hoses and the intake tube to see if its properly seated.

I'll definitely check that out, thanks.

I hate to say it because it's to easy but when is the last time the plugs were changed?

About 15k miles ago and I'm using NGK TR7ix's. Time for new ones?

 

[03cobra#694]

About 15k miles ago and I'm using NGK TR7ix's. Time for new ones?

Sure is!Change the fuel filter too.Clean the MAF.

 

[srl135]

you sure it isnt drivetrain slack?

Mine does this even up into 3rd gear but my bushings are toast so it will do it until i put a steady throttle into it...

 

[Savn4Mods]

I've noticed lately that the car's bucking a little bit especially in the lower gears... not like from slack in the drivetrain or anything, but it bucks while in gear, and I can't figure out what it is. I'd search but it's not working right now... any clues?? Is this normal?

:shrug:

Any recent work been done on the car? If so, what? Is it while you are at a steady throttle position like going through the gears normally?

 

[SLEEPERSTATUS]

Sure is!Change the fuel filter too.Clean the MAF.

how do you clean the maf? sorry for the newbie question:shrug:

 

[Savn4Mods]

how do you clean the maf? sorry for the newbie question:shrug:

A company named CRC makes a MAF specific cleaner. Got mine at O'reilly. Remove the MAF from the car and follow the directions exactly as they are on the can. Here's a link:

CRC Industries Automotive Product Detail

 

[SLEEPERSTATUS]

A company named CRC makes a MAF specific cleaner. Got mine at O'reilly. Remove the MAF from the car and follow the directions exactly as they are on the can. Here's a link:

CRC Industries Automotive Product Detail

right on thank you bro:beer:

 

[03cobra#694]

A company named CRC makes a MAF specific cleaner. Got mine at O'reilly. Remove the MAF from the car and follow the directions exactly as they are on the can. Here's a link:

CRC Industries Automotive Product Detail

:rockon:
Yep,that`s the stuff.

 

[99stanger]

Is when its warmed up too? I know my cobra and most manual cars will sort of buck in the lower gears if the car is cold.

 

[Posi]

Sure is!Change the fuel filter too.Clean the MAF.

If this doesn't fix it then you might want to get the tune looked at.

 

[CobraBob]

Is your idle smooth? And how long have you noticed it? I wondering if you have a bit water in your fuel tank. Possibly from some bad gas. Just a thought. I'd toss in a can of Dry Gas just to be sure.

 

[04cobra13]

you dont have a blown frps do you?

 

[jm@ReischePerf]

you dont have a blown frps do you?

A possibility.

 

[AzianStang]

Sure is!Change the fuel filter too.Clean the MAF.

Gonna do that this weekend hopefully!

you sure it isnt drivetrain slack?

Mine does this even up into 3rd gear but my bushings are toast so it will do it until i put a steady throttle into it...

I'm pretty sure it isn't, but I know what you mean by applying steady throttle... it's as if you have to really focus on applying gas just to keep the car from rocking back and forth...

Any recent work been done on the car? If so, what? Is it while you are at a steady throttle position like going through the gears normally?

No work done, but the car will do it normally shifting through gears just driving along. It feels like it's rocking back and forth. I even granny shift and it does it.

Is when its warmed up too? I know my cobra and most manual cars will sort of buck in the lower gears if the car is cold.

I was thinking the same thing... maybe it's a temp issue. When it gets warm it seems to get better, but I'm not too certain... I'll pay more attention to this.

Is your idle smooth? And how long have you noticed it? I wondering if you have a bit water in your fuel tank. Possibly from some bad gas. Just a thought. I'd toss in a can of Dry Gas just to be sure.

Smooth idle. I've noticed it for almost half a year I'd say. It's actually not that bad but it IS noticeable to me.

you dont have a blown frps do you?

I told me Cobra buddy about this issue, and he told me about the FRPS issue. He never had it on his 03 vert while he owned it, now the new owner is complaining about this same issue. He said something about the 03-04's having this problem but I have no clue how to address it.

I was also gonna tell you guys, I don't know if this has anything to do with this problem, but when going WOT sometimes the car will hesitate as if it's not getting fuel, like a huge belt slip, and suddenly pick up. It's like a huge, hesitating buck. It does it at random. I'll shift quickly into second or third, and the car will roll for half a second, then all of a sudden jerk and continue moving forward...

Thanks for all info so far.

 

[jm@ReischePerf]

I'll shift quickly into second or third, and the car will roll for half a second, then all of a sudden jerk and continue moving forward...

That just sounds like the normal shift hesitation issue, check out "PPRV delete".

Your other issue sounds more like a driveability thing. If it gets worse or the car starts to run real badly or not at all then pull the elec connector off of the FRPS and see if it it runs better.

 

[hotcobra03]

bucking

a couple of things,first is check engine lite on?plugs gapped to much,and oil leaking onto cop.are what problems i have found on mine,,also mines stock and it runs best with stock plugs..i use 12`s not 32`s.and gapped at .35..and i have this problem now as we speak,but i have oil leaking onto #8 plug.if i clean it its good for a couple of days than jerks again when oil fills the hole.it jerks while trying to drive as easy as you can going slow:beer: