I'm running a 5mic in the stock location and a GDP 2 mic. I also have an electronic fuel pressure gauge reading after the 2 mic and before the CP3.

Since my gauge is after the filters, in my mind I should be able to use the gauge to give me a hint as to when my filters need to be changed.

My pressures run between 7-10 and have since I've installed the 2 mic.

I know some guys on here change their filters rather frequently, but I'm wondering if they may be a little overzealous if I'm indeed correct in my logic. My 2 mic has 12K miles on it and my 5 mic has 10K. I appreciate the comments.

 

When it drops a couple of pounds at idle change the stock filter. I change at 8,000 - 10,000 miles. It depends on how dirty of fuel you get. With 2 filters you almost need one inbetween the two to be able to know which one to change.

 

I have an '04 and have the same set up that you have, except I installed the Walbro pump at the time I put the GDP 2 mic. filter on. I did that at 914XX miles in Oct. of '06 and I'm at 142XXX now. I've had 2 pressure drops since the install, both caused by the 7 mic. clogging from bad fuel. Replaced the 7 mic. each time and pressure went right back to normal. I have yet to change the 2 mic. spin on, though I carry one of each just in case. I have changed the 7 mic.filter since installing the 2 mic. though I've seen no pressure drops. Just for piece of mind I suppose. The 2 mic. alone is a great peace of mind mod. I can't see any reason why you couldn't extend your change intervals based on pressure. Others may know of some reason I haven't considered and hopefully chime in.

 

We share the same logic. I'm driving cross-country next month and now I'll toss in the spare filters.

 

I too carry a spare for everything. Hoses, belts, fluids, filters etc. I have the 5 micron Baldwin in the Stock container and 2 micron GDP. I am seeing 11PSI at Idle and cannot pull it down below 9psi hauling my big trailer. I have never noticed a drop in PSI. I change my stock filter every 5,000 with the oil and do the 2 micron every other change. I did change the 2 micron recently when i noticed some rust around the upper lip of the filter. Rust had not entered the fuel system so I put a little oil around the lip of the new filter..