4.0L power improvement???
 

I have a 1991 Land Cruiser. It has the under powered 3F-E 4.0L strait 6. I just went trough and tuned it up (plug, wires, cap, rotor, fuel filter, timed it, and changed every fluid in the vehicle). It has 140-150 psi across all cylinders on the compression test and 60psi for fuel pressure at the rail. The truck has 141,XXX miles on it. I also put a K&N air filter in. This made the truck run MUCH better but still way under powered for how large the vehicle is. I was thinking about hollowing the cats and changing the muffler, I really don't want to make it loud but that is the only other thing I can think of since there are no after market performance parts available. Any suggestions for more power?

Check out www.ih8mud.com, its the Land Cruiser website and find there's more info.

Sorry its a 3FE... bout all you will get. Pretty typical.

my 88fj62 has the same engine. the stock engine doesnt have alot of power. alot of guys ditch the stock one and put v8s or diesel engines in them. for more power

I did a full tune-up (plugs, wires, cap, rotor, and including ALL fluids), put a K&N air filter in, adjusted the throttle and kick down cables (massive improvement), and adjusted the timing by ear (literally doubled the power it has driving down the road), and hollowed the catalytic converters and put a cherry bomb turbo muffler in place of the OE muffler. Its a good sound but just a hair louder than I wanted but it helped power noticeably. So, over all the power is way up and my mpg went from 10-11 in town to average of 14 in town. Thanks for all your help!!

wow thats great to hear! i have a cherrybomb on mine too and i cant go through parking garages without setting off car alarms