Engline Light On: Error Code P0301, P0302, P0304

[WI4FEN]

Hi Everyone,
Really hoping for some help here.

Ok here we go,
I have a 2000 Honda s2000 with 64k on the clock.
Engine light has been on for weeks. The car is running fine with no obvious engine issues (i.e. no misfire, kangarooing, noises), only slight problem I have noticed is that when the engine is warm and you start the car, it almost stalls but after that it idles fine. If you rev it a bit when it's about to stall then it idles out fine, this is JUST when i start it when it's warm though. Apart from that she runs beautifully, V-tecs and runs perfect.

I first had it looked into at honda 2 weeks ago. They said the error code pointed to the spark plugs. They discovered the spark plugs were coated in some vaseline/silicon mixture, which they thought was odd. The plugs were changed by the previous owner about 5k ago you see by a non honda garage. They cleaned them up the best they could, reset the light and sent me on my way (£30). No need for new spark plugs they said.

30 miles later, the light came back on again whilst the car was sitting idle at the lights. Again no symptons what so ever.

I had it looked at honda again and the error code it put out was: Misfire P0301, P0302, P0304. No random misfire though. They said it didn't do it consistently enough for them to diagnose the problem and that I would need to leave it with them for 2-3 days for testing at £70/hr!!! Just to diagnose it. They turned the light off again and sent me on my way free of charge.

As expected about 30 miles later, the light came back on again whilst the car was sitting idle in a traffic jam. Again no symptons what so ever - engine sounds fine.

I've tried resetting the engine light by pulling the 7.5 fuse out, and after about 6 miles it will come back on again. No symptons when it comes on, the only common thing is that it tends to be whilst the engine is relatively warm and idle.

Has anyone got any ideas on this one? I dont really want to fork out hundreds just for honda to look over it and then not find the problem again. It's also due for a major service (60k) which is a bit behind schedule. However, I am willing to go to Honda if I have a good direction to point them in.

Any ideas would be greatly received!!! Many many thanks in advance. Stressing out about this one!

(I've done the tap MAP sensor test, which made is stall at idle a few times afterwards when driving but now it's recovered and is back to normal.)

[gomarlins3]

0301 is cylinder 1 misfire detected
0302 is cylinder 2 misfire detected
0304 is cylinder 4 misfire detected.

I have no experience with this, but if you have tried the MAP test, i would try replacing the MAP and see if that helps. Other than that, sorry, I can't be any help. The software I have only diagnoses the CEL's it doesn't tell me how to fix the problems.

[WI4FEN]

Thanks for your response, really appreciate it.

Do you think that when i did the MAP tap test and it made the car randomly stall during idle for 3 miles that the MAP could actually be the cause of the engine light coming on and misfire errors?

Do you have any idea how much the MAP sensor would be to replace and is it something I can at home? i.e. very straight forward.

Thanks so much for your help.

[gomarlins3]

This thread may help.
http://www.s2ki.com/forums/index.php?showtopic=386868