1999 4.0 4x4 extended cab.
Changed the maf sensor, and the two upstream o2 sensors and the bank 1 and 2 o2 sensors are still reading lean. You can smell gas when it's running and I get a hesitation when accelerating at times. Can't figure out the problem

 

maybe a vacuum leak? you can use electronics cleaner, brake cleaner etc. to check the hoses. if u spray near it and idle increases you got a leak. it maybe hard to hear the leak if you've had it a while it could sound normal to you. but thats just a guess. good luck.

 

I will have to try that tomorrow. Thanks

 

Just to clarify when I said "spray near it" I meant like all around the vacuum hoses. Key to the spray stuff is it says "extremely flammable" on the can. Thats what causes the idle to slightly increase as it sucks it into the intake if theres a leak. But I wouldn't do it with the truck hot. That's asking for trouble since hot headers and combustable aerosols don't play well.

 

Check pcv valve elbow