This info applies to a Workhorse W22 series chassis.
The first step would be to clean the air flow sensor. Second would be to check your air filter, if it's a oil version, change it back to a dry type.
MAF cleaner can be purchased at most auto parts store, the hard part will be gaining access thru the right wheel well.
Others will probably have additional suggestions.
Fred and Bonnie
2005 Dolphin LX 6375
Abby, Ruffles & Scarlett, "The Cats"