Well, I am very suprised that no one else on the forum has had the P0304 code. There must be something really wrong with my car.

 

I had a P0303 code.... I couldn't track down the problem for a while, then it turned out my injector plug for the #3 injector was coming off. Mind you the car was 2 weeks old at this point and stock. I first checked plugs/coils as you did, then I started checking injectors and noticed that the connector was lose. When I pulled it off the plug itself was cracked. This was on a new stock Evo. I fixed the connector and put it back together, problem solved.

- Steve

 

Thanks SuperHatch! This is exactly what I was looking for. I'll check the injectors next.

 

Hope that's your problem, but I don't think broken injector harness plugs are a common problem with these cars... good luck!

- Steve

 

I just picked up my car a couple of weeks back and my buddy loaned me his tool and I too have a P0304 code. You can hear somewhat of a miss at idle but it runs fine. When I bought it they told me it was probably the gas cap not being fully tightend. Yeah...right. I love how a salesmanager becomes a tech when trying to close a deal. I am under warranty and will be taking it in shortly. What became of your P0304 code?

Dave

 

Well, it's a long story, but I'll try to tell you. I went to the dealer and they said that I was using race gas and that it may be clogging the injectors. They reset the ecu and give me a bottle of fuel injection cleaner. At first, I thought they were full of it, but the code didn't come back for a while. I was getting almost every time I started the car. I do use race gas at times for added safety in the 110 degree temps I drive in. Just two or three gallons of 100 per tank. The code eventually camevback after adding the fuel injection cleaner. So, I went back to the dealership and bought several bottles of the fuel injection cleaner. I ran two bottles in one tank with no race gas. I used a total of three bottles all together. The code didn't come back for several weeks. More cleaner and no more code. I am keeping my fingers crossed that it doesn't come back. To make sure, I run a tank of Shell 91 with my racegas every once in a while. Shell is supposed to have more cleaners in their gas, but the gas is crap for performance. I haven't had the code now for about a month. I am keeping my fingers crossed.

Not sure if this is related or not. I got the P0304 when I installed a Vishnu Stage 1 on my car. I lost 500 rpm of spool up. I went through all kinds of crap to figure it out. It turns out that I had a vacuum leak leading to the turbo, I think causing the slower spool. Anyway, I also got Samco hoses. So, I believe I had a vacuum/boost leak that is now corrected. The idle is better and I don't hear that miss at idle that I used to hear when I had the P0304 code. Plus the car pulls cleanly to 7800rpm now. Boost hits hard and strong.

I am going to add a fuel injection cleaner once a month just to make sure the injectors are working fine. Maybe I am being neurotic, but I think it will help. Hope this helps!

 

I dropped my car off at the dealer this morning for the P0304 and they are doing a reflash as I type. The suspension noise turned out to be the upper control arm coming loose. All should be good again.


Dave

 

Is this true? I always thought the Shell V-power was supposed to be pretty good...? I wonder if our 93 V-power is any different from your 91.

 

As far as 91 oct goes, I think Shiv said Pro Power 76 was the best. I think there is a thread Vishnu forum with dyno results. When I put in Shell 91, my gas mileage went down as well as performance. It isn't confirmed by the dyno, just the butt dyno.

 

Doesn't the factory flash stop your ability to get an aftermarket flash? I think it also erases your aftermarket flash if you have one. I didn't get the P0300 dealer flash because of this. Besides, I am not sure the dealer flash will help with an idling p0304 issue. I thought is was for the folks that were getting the 5th gear drive train noise p0300. Not sure I am correct on this.

 

I really hope not because that's the 1st thing I want to do after getting a 160* Rally Art thermostat.

Dave

 

Ah, we don't have 76 around here. Just Shell, Exxon/Mobil, BP/Amoco.

 

https://www.evolutionm.net/forums/sh...ighlight=p0300

Check this tread out. I would call Vishnu to confirm.