Sc 400 99k Mi. When car is cold it's perfect but once it gets warmed up after bout a mile or so it starts to lag when applied gas. It will bog down for millisecond and act like something is putting pressure against gaining acceleration. Only at low roms tho but still with hesitation and not giving its full 100%. Does it at any speed too. And only when warmed up. Have replace spark plugs fuel filter and had toyota dealership do efi/injection system cleaning. I have ran car without gas cap too still no change.
Please help Noone can see to find issue.

Email - ivipalldayx@live.com

 

 

Step number one in eliminating SC400 hesitation or stumbling is to jumper the fuel pump relay to stop it from going into the low speed setting. There are several threads that detail how to do it and it will cost you nothing. If it still acts odd after that there are some other options but the relay is where to start.

 

Is your SC a later model that has the drive-by-wire setup? Perhaps it may be related to that if so.

 

I'm taking to mechanic this next week. He said it may be coolant temperature sensor or idle air control or mass air flow. Will run diagnostics next week and let you all know of results.