Recent changes, on again off again CEL

[jmarch1122]

I had been driving around for a few weeks with a CEL that I knew was for AFR too lean. Then I went and installed my hpfp stage 2 pump and 142 BAR valve. Then I had the garage scan for codes and there were 3-AFR too lean, and an EVAP sensor problem, and another having to do with the EVAP but 'pending'. The mechanic cleared the codes, and they stayed off for a couple days, but the CEL came back on when I went into high boost. The light went away after an over night, then came back. I disconnected my battery to do some other things and when I reconnected it, the light disappeared, just to come on again when I went into high boost again 2 days ago. I haven't been able to confirm that the CEL is still for the EVAP sensor, but it seems like it right? Im not sure how to proceed, assuming this is the problem.

Other symptoms to note:
I am noticing that my MPGs are less than ideal. Highway driving is good, but around town I seem to be going through a lot more gas than I expect to.

When I accelerate gradually in low gears, it doesn't come on smoothly. The car sort of surges, on/off/on/off. It is pretty much only noticeable in 1st and 2nd gears and under 3500 rpm.

I just replaced the fuel filter thinking that might be partially clogged but I haven't noticed a change yet. My next step is to change out the coil packs and spark plugs.

I know I have to confirm that the CEL is for EVAP before I can fix that, but does anyone have suggestions for the non-linear acceleration?

[bman005]

Get some fault codes for us if you can. We'll be able to help a lot more if you do.

[jmarch1122]

code is P2404.

searching says it could be a bad electrical connection, or a faulty LDP. Anyone know where I should look for the electrical problem before I replace the LDP?

[80sGuy]

Mechanic "cleared the codes"; it's like sweeping dust under the carpet. He has to first find the fault then correct the problem, clearing codes won't do any good except for them to pop right back at you again.

[jmarch1122]

I agree, clearing the codes wasn't meant to be a solution. I had to get the AFR too lean cleared anyways after the new HPFP was installed, and he cleared the other to see if it would come back on. P2404 could be something as minor as a loose gas cap. Apparently this fault has no effect on the car at all, its just annoying to look at the light, and especially to explain to to people who get in my car and see it.

From my reading, most people that get this code have an issue with not being able to fill up their gas tank all the way, or having the pump repeatedly shut off from pressure not being purged. I don't seem to have that problem, which is good, but I still would like this cleared up, and I don't like taking my car to a shop for something I could do myself. All the related threads I found on AZ were from 2008, so I didn't bother resurrecting one. I was hoping someone in the present might have some advice.

[80sGuy]

I agree, clearing the codes wasn't meant to be a solution....

From my reading, most people that get this code have an issue with not being able to fill up their gas tank all the way, or having the pump repeatedly shut off from pressure not being purged.....I had the P0089 popped at me when my tank was low, I narrowed it down to the Thrust Sensor.

[jimrobbington]

Take off the n80 and see if you can blow through it. That was the cause of my evap cel. You should not be able to blow thru it in either direction. It's like a 30 dollar part. You will need new hose clamps, because you will have to undo the oem one-use clamps.

Here's a pic of the n80.

http://i366.photobucket.com/albums/oo109/jimrobbington/2011-09-19113216.jpg

JR

[bman005]

For the P2404 fault there is a bulletin to check the vacuum source for the LDP pump. it is on the Brake booster vacuum hose. Check to see if the nipple has broken off