Jerking Vette
Thread Starter
Heel & Toe
Joined: Sep 2009
Posts: 19
Likes: 1
From: Tonga, south pacific! far from parts!!
Jerking Vette
Having trouble with this one,
My car jerks pretty badly when I am in gear and at low rpms.When I give it gas it clears up, I now run the car in higher rpms to keep it ''smooth''.
I have gotten into a rotten habit of pushing in the clutch to smooth it out, this I know would wear the clutch out sooner and so I now pull it out of whatever gear I had it in and shift to 2nd or 1st to run it in higher rpms. Slower speeds are really bad, its that first bit of gas that I give it that sends me into a bobble head madness.
Hope you know what I am talking about
Thanks
Ben
My car jerks pretty badly when I am in gear and at low rpms.When I give it gas it clears up, I now run the car in higher rpms to keep it ''smooth''.
I have gotten into a rotten habit of pushing in the clutch to smooth it out, this I know would wear the clutch out sooner and so I now pull it out of whatever gear I had it in and shift to 2nd or 1st to run it in higher rpms. Slower speeds are really bad, its that first bit of gas that I give it that sends me into a bobble head madness.
Hope you know what I am talking about
Thanks
Ben
Race Director
Joined: Oct 2005
Posts: 11,770
Likes: 175
From: Rolla Missouri
2021 C4 of the Year - Unmodified Finalist
St. Jude Donor '10 thru '25
What transmission, ZF6 or 4+3?
What speed and what gear?
Naturally you will experience what you describe if you try to drive 20mph in 6th gear.
So, give out all the details.
What speed and what gear?
Naturally you will experience what you describe if you try to drive 20mph in 6th gear.
So, give out all the details.
Thread Starter
Heel & Toe
Joined: Sep 2009
Posts: 19
Likes: 1
From: Tonga, south pacific! far from parts!!
86 4+3
It seems to happen at any of the 4 gears in low rpms, maybe around 2-5 mph when in 1st, its at its worst in 1st and 2nd.
I will be idling in 1st and give it a bit of gas and it will start jerking away.
It seems to happen at any of the 4 gears in low rpms, maybe around 2-5 mph when in 1st, its at its worst in 1st and 2nd.
I will be idling in 1st and give it a bit of gas and it will start jerking away.
Heel & Toe
Joined: Feb 2010
Posts: 23
Likes: 0
From: Hobbs NM
I had another car do something like that too and it was the spark plug wires. I don't know how much the throttle position sensor is but if it's not much I'd recremend changing that first sence it's really easy to change.
Thread Starter
Heel & Toe
Joined: Sep 2009
Posts: 19
Likes: 1
From: Tonga, south pacific! far from parts!!
Alright I put new plug wires and a new TPS in. It still shakes!
It does not seem to do it when its cold, and it happens the most when I am slowing down in gear around 4-8 mph, when I touch the gas it starts shaking. It would happen if you did a California roll at a stop sign and when you touch the gas peddle to pull away it would start shaking pretty badly. Anymore ideas?
Thanks Guys
It does not seem to do it when its cold, and it happens the most when I am slowing down in gear around 4-8 mph, when I touch the gas it starts shaking. It would happen if you did a California roll at a stop sign and when you touch the gas peddle to pull away it would start shaking pretty badly. Anymore ideas?
Thanks Guys
Last edited by Left Hand Drive; Dec 18, 2010 at 03:26 PM.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
Le Mans Master
Joined: Jan 2006
Posts: 5,620
Likes: 206
From: Orlando FL
Suggestions:
Check fuel pressure - perhaps change the fuel filter
Check for vacuum leeks and EGR
Check timing
Possibility of weak spark - (I know, slim)
Fuel injectors going bad
Can you get a scanner on it and check fuel trim if that year displays it.
Check fuel pressure - perhaps change the fuel filter
Check for vacuum leeks and EGR
Check timing
Possibility of weak spark - (I know, slim)
Fuel injectors going bad
Can you get a scanner on it and check fuel trim if that year displays it.
Safety Car
Joined: Oct 2007
Posts: 4,426
Likes: 229
From: Pennsylvania
You have 330 ft. lbs. of torque with this car! You can't drive it as though it were an automatic at very low speeds unless you push the clutch in. If you start to give it the gas at very low speeds, the car will definitely jerk you around. Learn to use the clutch and gas at the same time to adjust for the jerking sensation.
Instructor
Joined: Nov 2009
Posts: 162
Likes: 0
From: Houston Texas
You have 330 ft. lbs. of torque with this car! You can't drive it as though it were an automatic at very low speeds unless you push the clutch in. If you start to give it the gas at very low speeds, the car will definitely jerk you around. Learn to use the clutch and gas at the same time to adjust for the jerking sensation.
But on the other hand it seems like it could be a misfire. When my plug wires were roasted on my previous car it would go low rpms real rough but clear up as you got up in rpms. When was the last tuneup?
Thread Starter
Heel & Toe
Joined: Sep 2009
Posts: 19
Likes: 1
From: Tonga, south pacific! far from parts!!
Fourspeedvette- I wish that was the case! People said the same thing to me until I took them for a spin!! If all the old c4s did what mine is doing here chiropractors would be very busy
The car has 145K on it and it has been messed with a bit, I bet timing could be off, injectors old,ect ect. I will try and work through that list pcolt94.
Thanks Guys
383vett
The car has 145K on it and it has been messed with a bit, I bet timing could be off, injectors old,ect ect. I will try and work through that list pcolt94.
Thanks Guys
383vett
Last edited by Left Hand Drive; Dec 18, 2010 at 11:40 PM.
Burning Brakes
Joined: Aug 2004
Posts: 1,174
Likes: 125
From: Dunstable MA
St. Jude Donor '05
I chased a jerky action in 1st for a while. It only happened starting out on warm afternoons. If the engine is warm the OD can engage in 1st when the car is coasting, then disengage when the throttle is applied. At that point anything wrong with the power delivery is highlighted. My car got new injectors, throttle body, FPR, fuel filter and fuel pump before the problem subsided. The fuel pump was the last step but maybe should have been the first. It made the most improvement. The OD on/off is still a little bumpy, and a new TPS is my next move. Good luck with yours.
Safety Car
Joined: Oct 2007
Posts: 4,426
Likes: 229
From: Pennsylvania
I chased a jerky action in 1st for a while. It only happened starting out on warm afternoons. If the engine is warm the OD can engage in 1st when the car is coasting, then disengage when the throttle is applied. At that point anything wrong with the power delivery is highlighted. My car got new injectors, throttle body, FPR, fuel filter and fuel pump before the problem subsided. The fuel pump was the last step but maybe should have been the first. It made the most improvement. The OD on/off is still a little bumpy, and a new TPS is my next move. Good luck with yours.
Le Mans Master
Joined: Jul 2007
Posts: 5,043
Likes: 8
From: Tampa Florida
My car jerks pretty badly when I am in gear and at low rpms.When I give it gas it clears up, I now run the car in higher rpms to keep it ''smooth''. Slower speeds are really bad, its that first bit of gas that I give it that sends me into a bobble head madness.
Hope you know what I am talking about
Thanks
Ben
Hope you know what I am talking about
Thanks
Ben
To me - what your describing is an intermittant fuel delivery issue. If the fuel system is good then I'd look at the MAF circuit for issues.
Clean/check the MAF sensor circuit connections, clean the MAF sensor with "MAF cleaner" spray. If problems persist replace the MAF power relay and/or MAF sensor.
Burning Brakes
Joined: Aug 2004
Posts: 1,174
Likes: 125
From: Dunstable MA
St. Jude Donor '05
Is your car a manual or automatic transmission? If you have a manual tranny and the O/D is engaging in 1st gear, you've got a problem. In a manual tranny, it should only engage in 2'nd gear and above, but only if YOU turn it on. It does not operate by itself and definitely never in 1st gear. The O/D shouldn't be engaging even in an automatic by itself in 1st gear.
Safety Car
Joined: Oct 2007
Posts: 4,426
Likes: 229
From: Pennsylvania
Mine is a 4+3 and the OD engages in first when coasting just as the FSM says it will. It won't typically do this if the car is brought to a complete stop first and then requires throttle to get it going. In stop and go traffic when shifting to first without stopping completely, the OD will stay on after the shift into 1st, then drop out as the throttle is applied. Maybe it's not supposed to feel like anything, but if other things are amiss, it can send the car into a minor convulsion.
Burning Brakes
Joined: Aug 2004
Posts: 1,174
Likes: 125
From: Dunstable MA
St. Jude Donor '05
A 4+3 transmission is just that. Four gears with an O/D in the top three gears only. It will stay in O/D when you shift up or down through 4th, 3rd, 2nd and then the light may stay on for two or three seconds in 1st gear, but it should turn off as it does not operate in 1st. The button may stay turned on, but the transmission will disengage the O/D automatically while driving in 1st gear. I think you are saying this same thing but it just sounded as though you had an O/D 1st gear. That just doesn't happen with a 4+3.
Just to clear this up, 87FSM Chap.6E3-C8-1 "Manual Transmission" 4th paragraph . . . "By monitoring the engine parameters and the 1st gear switch, the ECM can determine what gear the vehicle is in. This will cause the ECM to keep the overdrive relay de-energized, if the vehicle is is 1st gear except during deceleration. . . . " So if you shift into 1st without stopping and don't apply the throttle right away, the OD stays on until you do.
My point to the OP is that under the driving conditions he is talking about this little detail might be triggering (not causing) his car's jerky behavior. My suspicion is that the gear change, throttle opening and fuel delivery get out of sync.
Last edited by Rich Silvestris; Dec 21, 2010 at 10:19 PM.