Home page

Topic: Misfire at full throttle

in Forum: C3 Engines

Already a Member?
Not yet a Member?
Register for Free!

Misfire at full throttle (1/4)
 9/22/21 8:55pm
Former Member

Send Private Message

Lakewood, CA - USA

1981 Corvette

Joined: 5/25/2021
Posts: 1

Getting on the freeway and at full throttle I get a bad backfire and sputter and no power. Back off the throttle about 1/2 inch 

and stops and runs normal.  At full freeway speed and I floor the pedal, kicks into passing gear without any hesitation. Only seems to be from dead stop and full load. Any thoughts.

New plugs, new wires, distributor cap, rotor and module. 

Our Sponsors help support C3VR
Re: Misfire at full throttle (2/4)
 9/30/21 6:55pm
Standard Member
Send Private Message

Germansville, PA - USA

1974 Coupe 358ci 4 speed Black w/Medium Saddle interior w/79 custom leather seats. . 1999 C5 Convertible, 6 speed, Atomic orange, Oak interior.

Joined: 1/28/2010
Posts: 828

Could possibly be a bad coil if you have one,  that breaks down under the heavy load. Just a thought.


|UPDATED|9/30/2021 5:55:59 PM (AZT)|/UPDATED|



Re: Misfire at full throttle (3/4)
 9/30/21 7:26pm
Adams' AppleLifetime Member
Lifetime Member
Send Private Message

Duncanville, TX - USA

#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

Joined: 11/8/2003
Posts: 19992

You list a cap, rotor, and module, but no coil? Could certainly be a coil failing, but I would also suspect a carb issue. 


Joel Adams
C3VR Lifetime Member #56    

My Link

(click for Texas-sized view!)

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

Re: Misfire at full throttle (4/4)
 11/29/21 2:59pm
Mark Laird
Limited Member
Send Private Message

Milford, DE - USA

1977 C3 Auto Coupe Lt Blue/Dk Blue Prev. 1968 C3 convertible 4spd Red 1984 C4 Automatic Silver 2000 C5 Automatic Black

Joined: 11/6/2021
Posts: 58

I had the same problem when I had my 68.. All I had to do was replace the manual fuel pump with a high performance one..Problem went away...Kept breaking down at full throttle..Old timer told me to replace fuel pump with high performance one and the problem was solved.


Good Luck!

Our Sponsors help support C3VR