My car was running perfect this morning on the way into the office and then after about 10 miles all of a sudden when I went to take off from a light my baby started to "sputter". The idle is perfect both before & afterwards this sputtering began and it only does it when trying to give it gas. Both in gear and free reving it sputters like it is missing or something. It shuts off just fine and restarts without a problem….engine is very quiet, etc. It just does not like me giving her the gas all that much causing it to sputter out the back tail pipes and also the engine to shake…but idling it does not shake. I got up on it a little before the sputtering about 3/4 throttle for a split second opening up the secondaries and all was good there and I was thinking to myself on this great sunny day how nice my car has been running and that I can't wait to take her to the 1/4 mile track again soon…..then 5 minutes later…sputter sputter sputter while under acceleration. I checked everything under the hood and all looks, smell, sounds normal including the oil, etc. The carb was tuned on a dyno about 8,000 miles ago setting the AF ratio but I don't know much else in what they did except that they said it ran really rich and now runs 12.5~13:1 under WOT and cruising.

I am hoping that this is something simple and have a feeling it is carb related so can something go wrong with the carb like this all of a sudden? Maybe it is time for Lars to work his magic :-)

 

"90% of all carb problems are ignition system problems."

 

I had a similar problem a couple of years ago. Car started and idled fine, but sputtered when giving it gas.

It is a Q-jet right?

My issue turned out to be the pin on the accelerator pump pushed out. That would be a good place to start.

If it is not that, I am sure some one more knowledable will jump in and help you out!

Good Luck!!!

 

Yeah...it is a Q-jet. The pin on the accelerator pump sounds like a good place to start looking. Funny how one minute it was running perfect and then all of a sudden it hates reving the engine but everything else is normal including start up and shut down.

 

I had the exact same issue - twice

turned out to be the coil both times

First time I replaced it with a cheap coil - next time I learnt my lesson and bought a decent one.

Check yours - it's an easy fix if thats all thats wrong & you can always borrow one and connect it to test - just cable tie it in for a quick run under load.

This is the one I bought after hearing many vetter's swear by them.

I haven't had a problem since

 

Took the 74 out for the first time today and I have the same f-in problem. It kinda hesitates / bogs when ngiving it a rev. When giving it constant gas say about 3000 rpm, I hinda hear a (for lack of a better term) blerp from the exhaust...quick revs up the rpm scale create a sort of backfire. out of the exhaust...
wtf is my problem???
LARS!!!! HELP!!!!!!

Stu

 

Long story short, New motor completly dressed, all new. First run after new motor put in she sputtered and choked then quit. Found the module in the distrib, was bad, replaced and she runs fine ecept every once in a while it coughs but keeps going. My carb is a barry Grant Road Demon Jr.625 brand new. Gas level shows 1/4 in window.
Any ideas
Thanks Randy

 

I had a similar problem earlier this year with my '77. I noticed the advance weights in the distrubutor were sticking. I cleaned everything to make sur the mechanism moved freely, changed the cap and rotor and problem was solved.

 

My car was running fine and then one day the points took a nose dive and I bairly got the car home.

If your car has points get a new set and see what that does.

James

 

Well....the mehanic has been trouble shooting the problem but unfortunately it has now gone away mysteriously. After it did this originally 3 weeks ago and I limped it back home....I let it sit for 2 weeks while I have been traveling, etc. and then had it towed last week Thursday to the mechanics. When I returned it started up perfectly after 2 weeks of sitting and idles nicely. I did not test it out myself to see if it was still doing this same problem but I did seem to notice that it was running smoothly as I gave it the gas to drive it onto the flat bed. The mechanic can't find anything wrong with the car and has driven it 20+ miles. He checked many items including the accelerator pump on the carb and he says all seems good. He is thinking it could be the fuel pump is starting to fail. What do you guys think? Fuel pump? After reading a few older posts it seems like this could be it...something related to fuel starvation, but I did not see any mention of this being a sporatic problem until the fuel pump officially fails.

btw...this is a L46 with a HEI distributor.

 

Stu -
First, let me remind you that you are just a hobbiest.
The problem sounds like a lean condition or fuel starvation. Replace the fuel filter in the carb and make sure you don't have any other filters anywhere in line. Then, check all your rubber hose sections between the frame and the fuel pump and between the gas tank and the frame - make sure you have no kinks that have developed after the car sitting over the winter. If all else fails, send me the carb and I'll give it a test run and setup for you.
Lars

 

Thanks Lars...you da man!
The hobbiest crack made me lol...Incidently I think that my neighbors "all Business" 84 crapped out on him...guess thats what happens when you never open the hood.
I'll follow your suggestions and see what I can find out.

Cheers,

Stu