What would cause 99 r1 to idle rough when warm

SOURCE: rough idle at stops

it could be any of the following:
time for a complete tune up ( plugs, wires, cap, rotor )
it could be thatyour ignition timing is out
you mayhave a clogged fuel filter
your injectors may be dirty
or you may have a vacuum leak
any of these could be the cause for your problem.

SOURCE: Rough idle until warm

HMM, ya ont get a code unless ya figure out how to read the morse code values the OB1's use. Hmm sputters, and rough idle can be from poor air circulation, as well fuel delivery.

first air.......inspect and clean your vacuum hoses, cracks and leaks will most notably ruin your day. as well as the performance of your ride. check the seal for your intake hose around the throttle body, then clean the ports in and around your throttle body as well. Bad air supply, poor idle.. follow me..


second is fuel delivery. Your getting your gas, thats evident, but are you getting the required amount. hard to guage unless you disconnect a line and test its pressure. so lets USE the KISS method.. KEEPING IT SIMPLE STUPID

first, check and or replace your fuel pressure regulator...

second, inspect condition of your fuel filter.

thrid, and certianly the last thing, your fuel pump. go in that order. or your gonna seriously annoy yourself when a 5 dollar fix turns into a 3-400 dollar fix.

SOURCE: MY 1985 300 SE IDLES ROUGH AFTER IT WARMS UP

hi,seem you have leak on intake manifold or rubber seal on injector nozzle,be careful drop a little amount on kerosene on intake manifold and nozzle,observe if your idling get high the is there,maybe renew rubber seal on intake gasket,ty

SOURCE: 89 corvette idles rough when warmed up

clean throttle body with carb cleaner

SOURCE: low rough idle

no-- plugs will not be the problem. More likely a vacuum leak from a hose left off somewhere. If a carby engine it will be the idle mixture screw out of adjustment check ignition timing is set at the correct advance point