B4000 running lean

[powdr4me]

I've installed a K&N intake and flow master exsaust (no headers) in my 98 b4000 and I've had issues with start up and terrible fuel consumption. I recall reading an article awhile back about having to send the computer back to have it set up to reflect the intake and exsaust changes...of course I can't find it now and was wondering if anyone might be able to help me out.

Oh and the check engine light is on full time and the computer tells me it's running lean. The Mass airflow sensor has been replaced.

Thanks

 

[powdr4me]

Newbie mistake...I checked out the 4.0 forum and found a lot of information that should help me sort this issue out. Sorry