Missing/backfiring

[Mark W.]

I completed my heater core replacement today and since it was such a nice day in Colorado, I went out for a short drive. However, I now have a new problem. At about 4300-4500 rpm, my engine starts to miss and when I back off the throttle, I also get a backfire. I didn't have this problem prior to my heater core replacement, so I must have mucked something up while working on it. I have the 327/350hp with stock intake and Holley carb. Any suggestions as to what I may have done?

[Mike M.]

Re: Missing/backfiring

plug wires? mike

[Mark W.]

Re: Missing/backfiring

That is one of the things I will check once the engine cools down. I will also check wires under and around the shielding to see if I pinched any.

[Mike M.]

Re: Missing/backfiring

i've had problems with the repo plug wires(carbon cored) once they've been removed. seems they are way too fragile and simply removing them from a spark plug(once they've seated on the plug with the heat of usage),results in loss of continuity. i use the repo wires for show only. wouldn't trust them any further than i could throw a dipstick. mike

[Mark W.]

Found the Problem

Mike, just as you suggested, it was a wire. The coil to distributor wire was corroded and nearly broken at the distributor cap.

[Dennis C.]

Mikie & I agree...

...I look at it from this point of view. Judging or Driving. If you want to play the judging game, you go with the dated repro wires to get through that process. If I'm driving, I use the steel core (Packard/440 type - actually get mine at Car-Quest) type of wires. Yea, ya gotta cut and make up the distributor end. Fool proof, last forever, deliver the goods. Frankly, with the reproduction wires I was buying a few years back, and paying big bucks for, they really didn't last worth a crap under cross country driving conditions. Not sure if the materials were lousy or what - I won't try to explain it or place blame, but the last set I removed after one year of service checked out with 6 of 8 wires WAY below servicable specs. JMHO and driving experience... Best, Dennis

[Randy S.]

Re: Mikie & I agree...

Dennis,
Will solid core wires interfere with the radio?

Randy

[Jack H.]

Re: Mikie & I agree...

Solid core ignition wires have a greater propensity to throw RF than the resistor core wires made from carbon impregnated nylon. But, if your engine shielding is properly in place, your radio ought to work OK....