Throttle tip-in issue/stumble (3.0 5-speed)

[workingonit]

Originally Posted by X5chemist

I've seen carbon buildup like that on a few old engines. My advice, drive it "harder"!

Back in the day, circa late '60's to early 70's, I was entrusted to do the upkeep on my parent's and grandparents cars. Still at home, in college, and having trained at a GM Tech school, I was the person given the job; my grandparents lived two houses down, and had an available garage (our house had one with a utility/washing room + storage roon, with no room for cars), so I at least had a place to work, sometimes.

P.S. I also did my younger brothers' cars, too, and also got the job of getting license plates and tags for everyone, all at once, one day a year (I often had to spend up to eight hours in line). And, I also dropped everyones' tax returns off at the post office drop-point (open 'til midnite). I was the "good son", and so it went.

My parents and grandad (grandmother hadn't driven since 1935) had helium feet (as opposed to my lead foot), so their engines woul get carbon-ed up, a lot. It didn't help that my grandad was a big Champion Sparkplug fan, and bought them in bulk for the family...I switched to better brands...A/C, NGK, Bosch later on), and all the cars had points ignitions, so no hot spark, at that time.

So, the first thing I'd do, is drive a car down to the freeway, do several full-throttle runs during a 10 mile loop, and then see whether it ran better. If not (though the "italian Tune-up" usually helped a lot) then I'd repeat the run, using Marvel Mystery Oil (in both carb and tank, killing mosquitoes with the resultant oil fog). After that, I'd do points & plugs. And change the oil (this maintenance cycle was done every 3k miles). Rinse/repeat.

I liked the use of additives from that early date, and have continued to use them ever since. My personal cars never seemed to get carboned-up (lead-foot, long commutes, drag racing, you know), but I'm sure modern ignition parts, and better gas and oil, all help a lot.