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Low RPM miss
I have an 89 camaro with a professionally built 383 stroker. Everything under the hood is new, I mean everything!
I recently changed out the Holley 750 secondary vacuum carb over to a 750 Holley mechanical double pumper and went up 2 sizes on the primary jets. Huge increase in power!!
I also set timing at 33 degrees at 3000rpm according to the builder's advice.
I also changed the ignition module to a Mallory Hyfire 6al. (The distributor is an HEI Mallory).
Since changing these three things I get a low RPM miss, up to around 1600 rpm's, that seems to get worse the longer I drive. Also, my plugs are almost blue in color and i'm assuming this is running much to hot or lean. (Accel shorty header plugs)
Which of these three changes should I look at first and what can I do to correct the problem.
I was told that a low RPM miss is electrical and a high RPM miss is fuel. True?
I contacted Mallory tech and they told me to check all grounds in the ignition module and braid all the wires together, change plugs to standard non resistors and make sure I have solid core plug wires. Did all this and it didn't make a difference.
Any suggestions or past experiences with this problem? I'm afraid of burning a hole in a piston or something.
Thanks
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sounds to me like a vacume leak. start it up (I'm assuming it misses at Idle ?)
Take your a hand held propane torch turn the gas valve on (don't light it:D)
and hold it over top of the carb and see if it smooths out. If it does you have a vacume leak somewhere or you are extremely lean....