11-20-2003, 06:30 PM
I recently got a 1974 El Camino, 350 V8, blue and white. A beauty.
Anyway, a problem. I was on the interstate last Sunday and I heard what sounded like a backfire, felt a jolt underneath me, and I lost about half my RPMs, but only for a second. With my foot on the gas it just climbed back up. It happened twice. Anyone know what it could be?
11-20-2003, 06:32 PM
Also, I get horrible gas mileage, around 12.5 mpg. How can I improve this? Any help is appreciated. Thanks.
Sounds like a perfect canditate for a carb. rebuild!
11-21-2003, 06:51 AM
My first guess would be the carb, also. However, since you just got it, it's probably a good idea to look at all of the plugs (#8 is a pain to get at and it's not unheard of for somebody to skip it when they change the plugs) and wires and check the timing and inside the distributor cap. There's always a chance that a weak plug wire is breaking down at higher revs and causing the misfire. Same possibility if the inside of the cap is dirty or damp or the cap is cracked allowing the spark to track inside the cap to the wrong cylinder. It's probably easier to eliminate the electrical possibilities before going to a new or rebuilt carb. As to the gas mileage, don't complain too loud. When I had a small block in my '74 with a TH350 and 323 gears I got about 9 mpg. I actually do a better now with the big block, 700R4 and 373's. Enjoy your truck, we're kind of the "red headed stepchildren" of the El Camino world.
11-26-2003, 07:36 AM
I get about 12 miles per gallon on my 1973 350 2 barrel. Sounds like a carb. problem, or possibly the engine has jumped timing via the timing chain. Put a timing light on it and double check the timing. It probably has an HEI electronic ignition system, and they don,t give much trouble until the module goes out, and then it will not start. Remove the fuel filter and blow through it (or replace it), to insure it is not plugged. Put your hand at the exit of the exhaust pipe, if its popping, you could have an exhaust valve sticking, if its sucking in, you could have an intake valve sticking, and most likely would need a valve job. Good luck!