Something is wrong, fix that instead of trying to compensate.
- Measure vacuum at MAP sensor with warmed up engine
- check for intake leaks around boots, hoses, clamps
- measure impedance of air-temp sensor
- measure impedance of engine-coolant sensor
Make sure someone hasn’t wired in one of those stupid pots that lets you “adjust” engine coolant sensor and changing data about operating conditions that’s sent to ECU, thus tricking ECU into injecting more fuel. Very few EFI systems need more fuel, they tend to tend too rich for safety. Toyotas are worse with 10:1 AFRs in high-end, wasting tonnes of fuel and power.
Only use PC to tune and lean out mixtures to optimum 13.5:1 once you’ve got system working perfectly stock (yours isn’t). Here what stock 300 AFR curve looks like, too rich in high-end at 12:1. Leaning it out results in +4% more power without any mods needed!
