I discovered a strange problem today driving down the highway. i was going up a very steep hill and naturally slowing down, so i stepped on the gas a little more to keep my speed up. Then i heard a weird pop, poppop which simultaneously caused the car to stop accelerating for a split second. also felt like it had no power. its a 68 coupe stock engine

the only recent work done on the car is headers, pipes ad flows (during which my mechanic "backed off the choke" on the carb...dont know what that means) and yesterday a new stereo unit and speakers were installed.

anyone know what my issue could be? the stereo guys left the old amp wires under the carpet, maybe their exposed tips are causing some sort of grounding effect? thats all i can think of.

any help would be very appreciated

 

have you driven up this hill before?

It sounds like when you load your engine it might be pinging. What happens is the fuel charge explodes in the combustion chamber before it suppose to. This often happens in high performance engines that run very high compression and get low octane fuel run through them...probably not your case. It could also be caused by incorrect timing being too far advanced. This could be your issue.

You would need a timing light to check it.
Can you get one?

-Gun

 

I agree, sounds like it could be detonation. Check the timing, both static and dynamic, and report back

 

are you running 91/93? if not do it...

 

fuel filter dirty maybe?

 

Staryfury probably hit it on the head. See lots of cars with total timing that is too high. Check that, if you don't have the ability, take it somewhere that REALLY knows how to time a car. Most don't. the only check initial. If you can't, throw some race gas in there. About 1/4 tank, put 2-3 gallons of 100. If it's pinging, it will magically go away until the next fill up. But that will give you an idea maybe even a little cheaper than a mech timing it.

 

Yeah, long gone are the days when a Sun distributor machine was a common shop tool=/

 

well good news.

i took it to a local mechanic who put it on a scope check machine and he found that the #2 cylinder was not firing as it should. they found that the ignition on that cylinder was not installed correctly. also a couple of other spark plug wires were a little loose.

road tested and no more misfiring and no more bogging down. im just happy it was such an easy fix and nothing major

 

Oh right on!

well then disregard my message about your octane question.

Instead dont bother with anything over mid grade. you wont notice a difference.

-Gun

 

Been looking for one. Are hard to come by. Funny. Now a day if a mechanic isn't told what's wrong by a computer, alot of them can't diagnose.