99 4.0 running lean

bumgrab · 12-12-2007, 10:27 AM

Hello, I have a 99' ranger with the 4.0L 4x4. The "check engine" light came on a little while ago and I used a friend's OBDII scanner to find out why. There were 2 codes that came up (mixture too lean bank #1 and mixture too lean bank #2) the truck does seem to be running fine. I cleared the codes to get rid of the light but the light came back the next day with the same trouble codes. I have since replaced the fuel filter suspecting a possible clog, didn't help. I had also been having trouble with the vacuum operated hub locks (I installed a set of AVM manual lockouts to solve that issue) But that got me thinking that there might be a vacuum leak associated with the old PVH system that might affect the air/fuel mix. any help would be very appreciated

jonmark1985 · 12-12-2007, 07:13 PM

Iim with you 100% on the vacuum leak, keep looking and listening!