yo Victor!
problem 1:
check for trouble codes; esp. if you have a CEL on;
EEC-IV Self Test & Connector Location & pics, Bronco & Ford by Ryan M
www.fordfuelinjection.com ? How To Run a Self-Test
Also, check timimg; look @ sticker under hood or on radiator shroud/top of rad. for info; remember to un-plug SPOUT connector.
Any signs of vacuum leak(s)?
Question 1
4.10 will give you the umppph you desire; here is a Gear guide that is good;
this Forum won't let me put in
Suspension Lift Kits, Body Lifts, Leveling Kit, 4x4, Jeep, Chevy, Dodge, Ford, Off-road Truck 's URL!
If the URL comes up Blank here again look in site in PART 1 under DRIVELINE and Scroll to General Information and look at:
Gear Ratio Guide for Larger Tires, general by roughcountry.com
Yes , it is an 8.8
Problem 2: hard to help you from afar; always good to remove - clean & lube/pack; hubs, bearings and spindle bearings; as well as doing brake caliper inspection, cleaning rials, lubing, etc.
check my web site out below for many tech article LINKS by fellow Bronco owners
Question 2: most others don't agree w/in-line pump removal; something about flow, etc.
here is a great RC 4" install article!
Rough Country 4 inch Installation in an 88 by Daniel T
4" Lift Install Write Up - FSB Forums
some tips in there by him as well as other posters.
Have new poly bushings ready and bought for radius arms, etc.; I like Daystar
A lot like
4x4ROCKSHOP.com - (877) 4x4-ROCK
they carry Yukon & Superior R&Ps
Try
Summit Racing - High Performance Car and Truck Parts | 800-230-3030 for $ too
Once you decide on a Gear Brand, search WWW by PN for best prices and then try locally for same or less $ incl S&H in comparisons.
GL!