A speed density system such as your '90 is not as tunable as say my '95 mass air equipped vehicle, but it can be done, just a bit trickier.

Also...I was going to say this.....you could liken adjusting the commanded afr on efi to adjusting the jet size in a carb.

 

i do believe you may be onto something man!!! makes no sense haha, specially how gas will be like, $3.67 in the morning then $4.01 in the afternoon!!!

 

i just today found out what one of the big reasons why my gas mileage sux is because my rear gears are 4:11L!! haha

 

wow thats nuts!! lol

 

haha, my dad took the truck to the shop and looked it over. needs all new bushings everywhere haha. thankfully georgia isnt in the rust area so the truck is a RUST FREE 1994!!!!!! haha. soo happy about that. ive also come to the conclusion that my rear axle may have a locker on it

 

Jack the back end up....Spin the passenger side wheel forwards, if the drivers side wheel spins forward too, its a locker...If the drivers side wheel spins backwards, its a open diff...

 

im hoping i have a locker haha. thatd be nice to have. i just know when i burn out, both burn marks are exactly alike lol. would a locker effect gas mileage on a 302/?

 

SCORE!!!!! thanks for the tip man!!!! i doo in deed have a locker!!!

 

im getting 11-12 with 3.55s and 31s

 

How does the power feel with that combo? I don't mind losing mileage as this isn't my daily driver, but sluggishness sucks. I ultimately want 33s but want to wait until I can do gears at the same time. Might look into some 31s in the meantime though if they're not bad. 235/75/15s just look a bit too small for a pickup in my mind.

 

what gear are u currently running? the power combo isnt bad i think really it depends on really what u want your truck to do..3.55s to me is a decents gear for arround town. its no race truck accel or top speed or any thing but i get up to speed fairly quickly thats not going over 2500ish rpms..iv thought about possibly 3.73s but still looking into them.

 

I have the stock 3.55 still. I was thinking 3.73 or maybe 4.10 if I went to 33s. No plans on towing, have other options for that. Mainly just an offroad toy.

 

I have 31's and 3.55's.. If I take off right, I can get to 60 in no time, buutt... Those are the times I get 8-9 mpg, if I take off like a sane person, I get to 60 in a few days.. Buut I get 11-12 one time I got 13.

 

to my knowledge i have stock 3.55s unless the guy before changed them but he pulled a trailer alot so i doubt it..mine dont seem to take days to get to 60 mayby i dnt have to 3.55s but to my knowledge he left every thing stock except a trans rebuild.

 

if you went to 33s id deff change gears,onetime i stuffed 33x13.50 tsl super swampers under my truck all the way around and it still went but u could tell it was kinda boggin the motor down..id change gears just to keep ur motor rmps up and help turn them tires.