Too Much Oil!!!!
Well, folks, I have a real nice 450 SEL '77 (German spec pwoer) with 64K on clock. got it last September from original owner. always garaged, serviced, but not used much over last several years.
I live in South Florida. Engine ran smooth and like a bear, with enormous gobs of pwoer, until about mid-to late May. Since then, it has started what I can only describe as 'fluttering' if I give it more than just a slight amount of gas on acceleration. No backfiring; just a fluttering absence of pwoer, until I ease off a bit on accelerator. Has been getting worse since late May.
Car looks great under hood, except for some dirt and grime, although I suspect plugs have not been changed in a long time.
Anyway, like a fool, I had Jiffy Lube do the oil change on May 14th. (I've only driven 1500 miles since then). Just today, I recalled that during the oil change, the guy said he was putting in extra oil maybe a quart or two more. I can't remember the reason he gave. They used 10W-30 at my request.
Based on story related above, the timing and the evidence so to speak, do you think that my 'fluttering' on moderate acceleration could be related to too much oil, compunded by using 10-30 in a beastly climate with short hop driving? I will pull a plug to look tomorrow some time, but I thought I'd get some opinions.