My 1988 22R reg cab seems to be rich. I say this because when it is idling, the fumes are fairly stout. I recently bought this truck back from my neighbors. Before I sold it in 2002 a buddy of mine ( Toyota Tech at the time) did a Timing chain, valve guide and we installed a 268( I think) Competition cam. I know that it was mild cam nothing radical. He also re- jetted the carb. The engine runs fine and starts easy, it just seems to be rich. I checked the the mixture screw and it was a little over six turns out, so I set it to 3 and half turns and tuned it per the manual then set the idle to 750 RPM. It still seems rich. Could something in the carb be bad like a rubber diaphram ? The carb has never had anything done to it other that the jet. I am just hesitant to tear it apart as it runs fine. Any help or tips is greatly appreciated.

Thanks,
22R88

 

What kind of carb?

Stock carb?

 

Yes !

 

If its a feedback carb check all sensors for correct operation any bad ones will default to rich O2 should be 200mv to 800mv at op temp if not going above 450mv change it other sensors like tp wil have 5 vref sig ground tps should be .5ish at idle 4.5ish at WOT not sure off hand what others u may or may not have.