Alright...I've been throwing the following codes on and off for the past 2 weeks:

- 17884 - EVAP Emission Contr. LDP Circ Malfunction/Insufficient Vacuum
- 17536 - Long Term Fuel Trim mult., Bank 1 System Too Lean

I tried to troubleshoot the problem this weekend by replacing all of the vacuum lines (which were pretty worn) with silicone ones, because that was my first though on vacuum leak...and also replaced the Secondary Air Pump (Smog Pump) because i've heard that is often the cause of some lean condition problems. Finally I installed a Forge 007 Diverter valve...just because I had the SAPump out and it was easy access.

So, i'm still throwing the same CEL codes...any ideas what the cause of this might be...? Thanks.
[confused]

 

The insufficient vacuum can be caused by bad vsv valves or bad evap canister pump on non intrusive evap systems. The lean condition could be caused by a dirty MAF or bad o2 sensor readings.

 

Most likely you have a vacuum leak somewhere in the vacuum line that goes to the leak detection pump. That would cause both codes to show up at the same time.