Help diagnosing 5SL misfire and stalling under load

[highsideheroics63]

I've been lending a hand to a friend with his 2003 5SL, and it's been quite the hassle recently. The bike keeps misfiring and stalling when we push it a bit. We've checked all the usual suspects, wiring, spark plugs, coils, everything looks good, with no apparent damage or loose connections.

Has anyone experienced something similar? Are there sensors that might have caused this issue? I'd really appreciate any tips or advice before we get into a more detailed diagnosis.

 

[littleMIX]

I'd check the crank or throttle position sensor, either one can cause misfires and stalling when the bike's under load.

 

[SugarKing]

Have you checked the throttle position sensor or any grounding issues? Those can sometimes cause random misfires like you're describing, could that be worth a look?

 

[Matt Edisa]

Chasing wiring and coils is fine, but too many people overlook the fuel delivery side especially aging pumps or clogged filters. At this age, it's almost always fuel starvation, but everyone wastes time chasing ghosts in the ignition system