Throttle not responding
Thread Starter
Intermediate
Joined: Jan 2018
Posts: 40
Likes: 0
Throttle not responding
I have 77 that I just put a new engine in. im just about to 500 miles on it, the car was running great until this afternoon. This morning, I filled it up with medium grade ethanol free gas. I drove it about 10 miles and parked it for about twenty minutes. When I started th car back up the throttle got weird, when I give it gas the rpms drop and it seems to bog down or lose power, I drove it for about 5 minutes and pulled over, gave it a little rev and it bogged down and died and now I can’t get it to fire back up. It also has a throttle body instead of a carburetor. Any ideas?
Racer
Joined: Jul 2003
Posts: 281
Likes: 50
From: Lima Oh
I have 77 that I just put a new engine in. im just about to 500 miles on it, the car was running great until this afternoon. This morning, I filled it up with medium grade ethanol free gas. I drove it about 10 miles and parked it for about twenty minutes. When I started th car back up the throttle got weird, when I give it gas the rpms drop and it seems to bog down or lose power, I drove it for about 5 minutes and pulled over, gave it a little rev and it bogged down and died and now I can’t get it to fire back up. It also has a throttle body instead of a carburetor. Any ideas?
Instructor
Joined: Aug 2016
Posts: 206
Likes: 18
From: Reedsburg WI
Thread Starter
Intermediate
Joined: Jan 2018
Posts: 40
Likes: 0
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,112
From: Crossville TN
I've actually put fuel labeled as "premium" in my car and had it buck/jump/miss...because that fuel was actually regular. The station just put regular in everything and sold it as mid & premium fuel. He was betting on the ECUs in today's cars "covering" his theft. Used a few gallons and put 'real' premium in it and the problem went away.
I couldn't prove it, but I chewed his **** out, anyway. No one in my car club will ever buy fuel there again.
I couldn't prove it, but I chewed his **** out, anyway. No one in my car club will ever buy fuel there again.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
2027 Corvette vs The World: Every Model vs Closest Competitor
Joe Kucinski
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
5 MOST and 5 LEAST Popular Corvette Model Years in History!
Joe Kucinski
2027 Corvette Buyer's Guide: Everything You Need to Know!
Joe Kucinski
10 Things C8 Corvette Owners Hate (But Won't Tell You)
Joe Kucinski
10 Best Corvettes Coming to Barrett-Jackson Palm Beach 2026!
Brett Foote
Every Corvette Grand Sport Explained! (C2, C4, C6, C7, & C8)
Joe Kucinski
Grand Sport & Grand Sport X Launch Alongside All-New 535hp LS6 V8!
Michael S. Palmer
5 Reasons Bad Drivers Crash & 5 Ways to Avoid a Costly Mistake!
Joe Kucinski
Is my vette stock?? HAHA
Joined: Oct 2015
Posts: 20,036
Likes: 9,157
From: Im not allowed to tell you
2020 C3 of the Year Finalist - Modified
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
vacuum leak, timing chain jump, bad vacuum advance or distributer mechanical advance seized. I've had same symptoms with all these causes over the years as well as the ones mentioned above. Any mechanical noise before all this happened that you remember?
Start with easy to hardest ( Check all your fuses, fuel supply [pump, filter, vacuum lines], then spark and timing) finally your ecu if your year has some sort of computer. .
When you say new engine, is it a crate or a rebuild?
Good luck, keep us updated
Start with easy to hardest ( Check all your fuses, fuel supply [pump, filter, vacuum lines], then spark and timing) finally your ecu if your year has some sort of computer. .
When you say new engine, is it a crate or a rebuild?
Good luck, keep us updated
Thread Starter
Intermediate
Joined: Jan 2018
Posts: 40
Likes: 0
vacuum leak, timing chain jump, bad vacuum advance or distributer mechanical advance seized. I've had same symptoms with all these causes over the years as well as the ones mentioned above. Any mechanical noise before all this happened that you remember?
Start with easy to hardest ( Check all your fuses, fuel supply [pump, filter, vacuum lines], then spark and timing) finally your ecu if your year has some sort of computer. .
When you say new engine, is it a crate or a rebuild?
Good luck, keep us updated
Start with easy to hardest ( Check all your fuses, fuel supply [pump, filter, vacuum lines], then spark and timing) finally your ecu if your year has some sort of computer. .
When you say new engine, is it a crate or a rebuild?
Good luck, keep us updated
Is my vette stock?? HAHA
Joined: Oct 2015
Posts: 20,036
Likes: 9,157
From: Im not allowed to tell you
2020 C3 of the Year Finalist - Modified
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
Hopefully its something easy that just isnt right and you can fix it yourself. I hate having to deal with companies over the phone.. Keep us informed, hopefully its an easy fuel system issue
Thread Starter
Intermediate
Joined: Jan 2018
Posts: 40
Likes: 0
So I let the car sit for a few hours and went back to it, it started right up and ran perfect.... for about 30 minutes, then i realized the rpm’s were starting to hang up and jump up so i drove it home. I took the air filter off to look inside the throttle body as a gave it a few revs, it kind of seems like one of the (maybe the two) back barrels of the throttle body closest to cab weren’t spraying as much fuel as the the front barrels. I don’t know if that’s normal or not, but I’d rev it and I’d get an occasional back fire as well. I put in some sea foam into the gas tank, maybe that will help. I bet I could go drive it right now and it would drive smooth for about 20 minutes and then it will start doing its funky thing. Maybe the correct term I’m looking for is the engine is stumbling??
Last edited by DavidNHarris88; Feb 5, 2018 at 11:00 AM.
Team Owner
Joined: Jan 2007
Posts: 53,648
Likes: 878
From: Southern Cal Ca
St. Jude Donor '22
So I let the car sit for a few hours and went back to it, it started right up and ran perfect.... for about 30 minutes, then i realized the rpm’s were starting to hang up and jump up so i drove it home. I took the air filter off to look inside the throttle body as a gave it a few revs, it kind of seems like one of the (maybe the two) back barrels of the throttle body closest to cab weren’t spraying as much fuel as the the front barrels. I don’t know if that’s normal or not, but I’d rev it and I’d get an occasional back fire as well. I put in some sea foam into the gas tank, maybe that will help. I bet I could go drive it right now and it would drive smooth for about 20 minutes and then it will start doing its funky thing. Maybe the correct term I’m looking for is the engine is stumbling??
sounds like heat in distributor is making it bad.
Is my vette stock?? HAHA
Joined: Oct 2015
Posts: 20,036
Likes: 9,157
From: Im not allowed to tell you
2020 C3 of the Year Finalist - Modified
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
Since its a new engine. Was the throttle body drained and cleaned since its beeen sitting. It could have junk in the filters or floating around internally that clogs it up when its been running a while. Either that or the fuel pump is failing. I got a jeep running that sat for about 6 years. It ran great at first but the pump started to slowly fail as the week went by. I would remove the throttle body and get it cleaned or rebuilt, replace the filter and see what your fuel pressure is
Thread Starter
Intermediate
Joined: Jan 2018
Posts: 40
Likes: 0
Today I plugged my little digital monitor into my throttle body (tells me engine temp, rpms, and a few other things) and I noticed when I rev the engine, the little computer was saying I hit 8,000 rpms, which can’t be true, it sounded more like 3,000. I wonder if a bad tach reading could be throwing off the air fuel ratio and making it run badly? Just an idea, any info?
Le Mans Master
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
I'd suggest a couple of things--
1-- Ignition Module
2 -- Spark plug wires leaking (or to close to)
and confusing the computer that's controlling the A/F.
1-- Ignition Module
2 -- Spark plug wires leaking (or to close to)
and confusing the computer that's controlling the A/F.
Team Owner
Joined: Jan 2007
Posts: 53,648
Likes: 878
From: Southern Cal Ca
St. Jude Donor '22
Thread Starter
Intermediate
Joined: Jan 2018
Posts: 40
Likes: 0
So today I installed a new coil, new ignition control module, and topped it off with fresh premium gas from a different gas station than what I used right before it started happening. It seems to be running better than ever, only time will tell tho. But for now it seems like one of those three things did the trick
Is my vette stock?? HAHA
Joined: Oct 2015
Posts: 20,036
Likes: 9,157
From: Im not allowed to tell you
2020 C3 of the Year Finalist - Modified
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
Good job on figuring it out