I have a 1990 Toyota pickup 2wd 22re 4speed, great little truck and have plans for it but when I driving down the road and I left off the gas pedal the cel comes on for a few seconds then goes away. When I get back on the gas pedal while cel is on it’ll stay for the few seconds I mentioned when I let off of the gas. Only ever stays for a few seconds but it does it almost every time I let off the gas pedal running down the road. The only thing I notice when the cel comes on is it’ll kinda do a nose dive and sounds kinda funny like almost misfiring but it’ll only do it for a few seconds then runs just fine afterwards. I guess I should mention past catalytic converter exhaust pipe is rusted out and no good, I don’t think from cat up to exhaust manifold has any leaking. Obviously needs a new exhaust just haven’t bought a new one. Don’t know maybe needs new o2 sensors or if it some other sensor?