Hello all,

I have recently purchased a 300SL (1990) and am having a problem with it. It hesitates upon accelerating away from a stop sign or traffic light. Car idles and runs fine otherwise, but just feels like it's going to stall when initially accelerating.

If I run the A/C it is worse.. probably because of the compressor load.

Car was driven only 6000 miles in the last four years before I bought it. Didn't pass the emission test (high HC) so my tech did the following:

-New cap, rotor, spark plugs
-Fuel injector flush
-Replaced air filter

Before I took the car to him, it actually stalled a few times. It had 5 gal of what I can assume was "old" gas (I know it was at LEAST one year old according to the previous owner). I added 15gal of fresh premium gas before dropping it off at the shop.

Questions:
-Is it the mix of 75% new/25% old gas that is causing the hesitation and will it be fixed two tanks from now?
-Should I put a new fuel filter on the car as a "guess" at the problem? My understanding is that the current filter is at least 5 years old.
-Assuming the tanks of fresh fuel & new filter doesn't fix it, what else could be wrong? I don't want to go changing parts (I could buy new ignition wires, for example) without knowing where to look next! I'd like to chase after the next "most likely" cause before I start changing expensive parts.

By the way, the tech was told to replace whatever necessary in the tuneup. I think we can assume that ignition wires are not the problem, as he would have called me to OK new wires if that was the case.

Thanks!
Neal

__________________
'83 300SD 335,000km (207k) mi SOLD
'87 560SL 163,000km (101k mi) SOLD
'86 300SDL 356,000km (220k mi) SOLD
'92 500SEL 250,000km (155k mi) SOLD
'90 300SL 140,000km (87k mi) SOLD
'01 S430 260,000km (161k mi) SOLD
'03 SL500 167,000km (104k mi) SOLD
'07 S550 4MATIC 235,000km (146k mi) SOLD
'07 GL320 CDI 4MATIC 348,000km (215k mi)
'13 GL350 BlueTec 4MATIC 170,000km (105k mi)
'14 SL550 72,000km (43k mi)