Hello... First of all I have a 99 GSR that will sometimes crank up and run fine and then when it gets to temperature at idle the rpms will jump up and down from like 750-500 like it wants to die. Not always but lately the motor has been misfiring in cylinder four and it sounds like something is wrong with my timing belt. I am replacing it soon and I hope this is the problem if anyone has any suggestions or know the problem please let me know as soon as possible. Thanks for reading...

 

Bump

 

uuhh... 1 cyl misfire usually is only a 50rpm drop.. could be a bad plug or wire honestly. pull the spark plugs and see if the 1 cyl thats misfiring is any different then the other 3. and timing belt wouldnt cause just 1 cyl to **** up.