Hi guys, I'm running a fairly stock and fresh 318 with Holley DP650, Auto 904, Mopar elec IGN...
I recently purchased the car (68 Dart Coupe), and all was well except for a vacuum leak, that I thought was the shaft in the Carb, so I sent it out for a full recondition with the most reputable shop here in Melbourne, Australia. Until I had the Carb overhauled, I did not have the issue I am posting about...
Since receiving the overhauled Carb, I still have a vacuum/ air leak - whistle issue at idle...
However, the issue I'm posting about for now, only presents itself once the car is properly warmed up, i.e. at least 15/20 minutes of varied driving, and perhaps after I've turned it off an back on. For instance, just now I've returned from the gas station (a 10min drive from my place) after filling with fuel, I then fired her back up and drove off fine, then after a minute or two the problem had returned. Prior to this trip I had replaced the following, as a mechanic told me I had an electrical problem, NOT fuel issue...NEW ECU Module, Coil and plugs as my suspicion was that my ecu module had gone bad, and thus was failing once it got hot...
Anyways, swapping out these items has not alleviated the problem... being that, once warmed up the car develops a bad miss/stumble whilst coasting/cruising/holding throttle steady, which goes away smoothes out completely under steady/hard acceleration. I find it weird that there's no stumble/miss under load/brisk acceleration, and also that I did not have this issue until I bolted up the freshly overhauled Carb..., Also weird, that IF it is electrical, and not fuel related WHY does it happen once the vehicle is hot?! But I'm sure you guys will know some culprits I can assess!! The mechanic who assessed it said I probably also need to bump up the timing - Could timing alone be causing my issue? Tomorrow morning I was going to maybe advance the timing slightly, and perhaps replace the Ballast Resisitor, as I bought one, but didn't bother replacing it yet. To be able to drive the car once the issue starts, I have to hold the throttle down 2/3, to 3/4 so that it doesn't stall on me, and work my 2 foot magic on the brake. I'm obviously a bit frustrated at this point and welcome any feedback, thanks:)