Have a friend with an '01 SLK230. She complained about rough running and poor acceleration. Pulled the codes the other day and they came up as 301, 335 and 336. I assume there is supposed to be a "P0" in front of each of those. P0301 is misfire cylinder 1. P0335 and P0336 are both crankshaft position sensor codes. The codes were reset and haven't come back on, but it's also only been a day. What would you think would be the approach to fix this? Plugs have not been changed, so it's due for them I think regardless. Could the MAF cause the P0301 code and it that the likely culprit?