It is worse when the engine is hot or it is really hot out 90F It is worse under load (uphill or two up) It stops as soon as I let off the throttle There's no backfiring. Am I running too lean? I'm considering getting a 3rd party DFO/TFI to richen it up a bit (plan on getting louder pipes soon too). Could the add-in help my problem? Anyone else have this issue? Thanks, Gary F.