BAD gas mileage 22re

[4runner_1249]

so i have a 1990 4runner with the 22re and last april or may i had to get the engine rebuilt because of various issues. it ran great up until now, i was getting on average 18.5 mpg which made me happy considering most of my driving is city. then i started to realize mileage dropping, first down to 16, then 14, and it keeps going lower and lower. it also is having problems starting. no idea if they are related at all. and a seperate problem ive been having is when it's idling, and i hit the brake, the engine RPM's drop down suddenly, and then as long as i hold the brake the engine revs up, and then drops down, and revs up again, etc. any help with any of these issues would be greatly appreciated:grin:

[Ibuildcorollas]

you'll probably just need to go though and start checking things, plugs, wires, plugged-cat?, bad 02, fuel filter,could be lots of things, your timing may be off BUT shouldn't be if you've never touched it

also check all your vacuum lines, including the one coming the master cylinder. any cracked/broken missing line will cause bad idle.

[85yotto]

TPS ! go get your TPS checked out. Also check your fuel filter. I would bet you have two issues one TPS is not working right and two your FF is old and clogged.
thats my 2cents

[bodo]

Check for trouble codes.

The idle rising and falling with the brakes pushed screams classic "Idle adjusted to high"