Diablo chip for a 1990 f-150 351
 

Just wondering if anyone has put one of these chips in a 1990 f-150 351 ecc iv system and if it makes a difference is it worth the money to put a diablo chip in this truck its a regular cab long box 351 e4od trans 2 1/2 inch lift
31x12.5x15 tires 4.10 gears just change the from 3.08s huge update I was get 10mpg and now getting 13.5 mpg with 4.10s just wonder if the chip is worth it. thanks any info will help

If by "worth it" you mean recover the lost mileage.... no. The chip will not do a thing for the mileage, any gain is offset by the cost of premium fuel. It will help power, but how much depends on altitude, engine condition, etc....

condition of engine
 

will it runs really strong and I live in minnesota so alitude hiw does that effected the chip will i loose mileage with this chip or stay the same thanks

Altitude effects gas vehicles, chipped or not, an average of 3% per every 1000 feet above sea level. Mileage tends to go up slightly, but you need to run premium fuel with the chip.