wsmarshall

A couple days ago I started my S2K ('03, spa yellow, 128k miles ... bone stock perfection) and saw several symptoms:

1) long cranking ... didn't start until I gave it a little throttle
2) big cloud of smoke in the exhaust ... smelled of gas
3) rough idle, and stalling if I didn't keep it revved around 2-3K.
4) the car would run OK at higher revs
5) CEL P0300, 0301, 0302, 0303, 0304, 01399 ... cylinder misfires - all cylinders

I poked around this forum ... searching by symptom and CEL code, and found several posts indicating a fuel problem.

Folks recommended valve adjustment, coil pack and spark plug replacement, fuel filter replacement, fuel pressure regulator replacement, fuel injector cleaning and/or replacement
One poster said the problem went away after he rebuilt the entire fuel system ... from filter to injectors, and the pressure regulator.

Given the responses from others, I suspected the fuel pressure regulator, because all cylinders were misfiring, the sudden onset of the fault, and the smell of gas in the exhaust. Throw in some of my own confirmation bias / wishful thinking, as it was one of the cheaper parts to replace.

I took it to my mechanic today and without prompting from me he independently confirmed that the cause was a failed fuel pressure regulator. I hadn't told him about my forum search. He's a good diagnostician, and got right to the problem ... I was gratified to know I guessed right and that this forum was hugely helpful.
The part (16740-PCX-003) isn't expensive ($250 at stealership for OEM, or half that at DeBernardi Honda parts) .

I'm posting here because the symptoms could be misleading - and finding the solution by part-swapping could have been expensive.

laughoutlloyd8

I'm just getting the same issues with my 05 s2000 with only 96500 miles on it. I only experience longer crank to start the car (sometimes I do have to hit the throttle to get it going) and also rough idling. It hasn't stalled on me but it sure sometimes feel close. I'm about to order a new fuel pressure regulator to see if it solves my problem

RolanTHUNDER

Now you have me wondering if my stock FPR that's been handling higher pressure from my AEM 340 LPH fuel pump tuned on AEM Series 2 ECU bit the dust while I was driving causing scary misfiring and now my car shuts off just as I try to start it. Swapped plugs, coils packs are new, swapped TCT, swapped MAP sensors just in case but nothing solved the issue. Apparently a larger capacity FPR is recommended when running a larger than 255 LPH fuel pump on stock rail. I had starting issues on cold starts where the car would miss the start and stumble on the first run and then when I pushed start the second time it would fire up. Had hard start issues on stock ECU as well but it always fired up the first time even cold back then.