Thread: Lean miss at idle

Stuff with this car never ends... I now have a miss at idle and will cause a very lean condition as soon as you feel the misfire. I replaced the plugs/wires/cap/rotor this past weekend and the miss just showed up today. This only happens at idle and AFRs are fine under load which leads me to believe my FPR is going out. Guessing the walbro 255 is too much for the stock FPR? Anyone have any other ideas what this could be?

- Bad injector out of the 4 - Q45 injectors
- Clogged fuel filter - Guessing its the same one from the factory
- FPR is going bad - FPR is stock

Kinda ruling out a bad injector or a clogged fuel filter because it is fine under load, unless the other injectors are making up for a lame injector and I have a really lean condition on one cylinder?

replace fuel filter, and install a fuel pressure gauge. cheap from jegs.com.
make sure the gauge is liquid filled. also, a good thing to note, you should be running a upgraded fpr to control the pressure.

a fuel pressure gauge would be agood place to start if you are thinking its a fuel problem

What brand plug wires did you use? With the sr20de engine I find a lot off aftermarket/ and OLD stock wires will miss at idle and work fine besides that?
Also check for a cracked sparkplug.. it does happen

Everything I replaced was from nissan. I'll be putting in a 300zx fuel filter along with a fuel pressure gauge. Just odd as hell that it only goes lean at idle but is fine under load.

Im a fucking idiot, ordered a nismo FPR, gauge, and a 300zx fuel filter. Was adjusting my TPS after warming the car up and notice that it really smells like gas and look down at the fuel filter and see this:



*&^*&^!! Well atleast I have everything to go 4bar now....