1967 250SL with a complete crap-out at 3000 rpm and bad stumbling on hard acceleration under that. Pertronix with Bosch blue coil. Checked fuel pump output (good), tinkered with timing and linkage adjustment (made small difference). Checked electrical connections. Voltage to coil good. Coil resistance good. Plugs looked good. Suspected the off brand plug wires with 11K ohms resistance and was just about to order a set, when I noticed a large original-looking capacitor on the + side of the coil.
Disconnected it and all was suddenly good. No stumbling, happily went to 6000. Go figure.
Cheers,
CT
