Car bucking untill i push in clutch !!!!

[lx2c6]

hey fellas , i have a annoying problem thats driving me crazy , heres the skinny on my woes , quickly heres what i got ,
brand new 302
forged bottom end
forged pistons
pro comp heads 2.05/1.60
24lbs inj
accufab tb 70mm+egr
ford motorsport maf conversion kit
73mm C&L
gt-40intake
smog delete
a/c delete
190lph Fp
3:73's
FP set @ 40
timing @13
erson cam 544/544''
new plugs , wires , distributor
new flywheel , clutch 2 yrs old , 70% life ( motorsport king cobra)
stock t-5
Heres the problem as im driving at lets say anywhere under 1500 rpm's the car will buck violently ( like it does when when a newbie driver first starts out driving stick and they let the clutch out with out enough gas and it bucks back and forth untill the clutch is put back in ) thats the same characteristic that my ride is having under 1500 rpm no matter what gear i could be driving in 5th and as soon as it goes around or under 1500 and i let off the gas it will buck. as soon as i hit the gas again it goes away and if i push in the clutch it goes away , same with parking lot driving i push in the clutch and the bucking goes away . I checked codes and i do have a speed sensor code along with some emissions codes ( prolly due to no smog) , i checked the speedo gear on the cable side and it looked fine , my car is a 87 w/o cruise control im not sure what else to check PLEASE HELP . sorry for the long novel , i appreciate any help and thoughts

 

[stangjunkie]

my car does the same in every gear between 1k and 1500rpm looking for good advice
(i also have prothane motor mounts so that may attribute to alot of mine)

 

[Flavadave4]

i have heard of people with an aggressive cam having bucking at lower RPMs, Mine does a little but i dont drive it much under 1500rpm anyhow!

 

[stangjunkie]

I have TFS stage one but lx2c6 has a hair more aggresive cam i think

 

[Flavadave4]

I wasnt sure about his, just offering my thoughts

 

[1FatPony]

that exact thing was happening to me a few days ago. I found out that it was because of my high idle. All I did was lower the idle and it was fine.
I had also put in a new 302.

 

[mob]

My car did this when I broke a bolt on the upper to lower intake. Had a bad vacuum leak. Fixed it and ran fine. Did the head swap, and broke another bolt in the same spot, ill be cruising at 35mph in 4th gear and itll violently start to buck until i push in the clutch, so im thinking its a vacuum leak. Get a vacuum gauge and see that you pulling enough vacuum.

 

[Deleted member 87397]

Sometimes that's just the tradeoff with a heavy duty cam, a lot of power and a grippy clutch. Mine does it too, but it's just the aftermarket clutch wanting more rpms in a given gear.

 

[dastang2]

mine does that with the f cam, nothing you can do about it except push the gas

 

[ninety15.0]

mine does it too...i think the only remedies are back the idle down and take some timing out of it. low end driveability goes to $h/t with HCI cars.

 

[bynummustang]

mine does that with the f cam, nothing you can do about it except push the gas

Exact same thing with me.

 

[projectfiveo]

my buddy has a freashly built 347 that does the same thing so i will besure to tell him to set his idle down some!

 

[Roland69]

my bone stock GT does this but not bad....just the idle drive bucking like it needs more gas pedal.

 

[1FatPony]

Mine idles around 700 and I have no bucking at all.

 

[vristang]

You need a tune if you are not happy with this condition.

The cam and the Injector/MAF mismatch are wreaking havoc with the puter.

Either get a tune or tuner
OR
Downshift to increase your rpms.


Good Luck
jason

 

[iwashmycar]

mine used to buck like that taking off (was like i was a nooB at drivin), mainly when the car was cold, this last weekend i put a new belt on, and as strange as it sounds, it doesnt do it anymore...odd, but im not complaining.

I had also taken my car down to the local NTB for a tire balance, and if they did somethin i dunno...probably just burnt half the clutch off...that could be it lol

 

[Black1987Stang]

playing with the timing on mine fixed the bucking for me...and cleaning the maf helped out some too