Local guy is selling a 2003 Evo with the following modifications

BUT just last week it threw a code P0300 "Random/Multiple Cylinder Misfire Detected "


It also seems that with cars that throw the code it becomes a on going problem is this true?

I saw a couple threads where people's engines threw this code after blowing....

Is there anyway that I can tell a harmless P0300 code vs a potentially engine blowing one?

the engine mods are:

- Vishnu Stage 1 Plus V390 kit includes the EXEDE piggyback computer.
- Dyno tuned approximately 390 hp on 92 oct pump gas
- 3" Catback Exhaust
- Helix 3" Downpipe
- HKS 264 Intake Cam
- HKS 272 exhaust Cam
- Two (2) HKS Adjustable Cam Gears set at (-3 Intake/-3 Exhaust)
- Ferodo Front Brake Pads
- Ferodo Rear Brake Pads
- Walbro 255 LPH fuel pump
- Autometer Carbon Fiber Boost Gauge
- Evo VII tail lights
- Grounding Wires, thicker gauge


Thanks in advance!

 

Does the light come on when you are driving or when the car is sitting there idleing??

 

The p0300 code is very common, especially with cams. I usually get it about once every 2 or 3 tanks of gas. Some people swear that its a problem in the transmission that throws the random code. I dont think its something to really worry about.

I would be more concerned with other things like the engines compression, the transmission and t-case.

 

It is something to worry about if he has a true misfire.

 

If you do a plug change and only get the code above 50 while cruising, its the same phantom P0300 we all get. 9 times out of 10 thats what it is.

 

About 50 while cruising is more than likley the transmission harmonic noise, at idle is either from cams or too much timing at idle but if he gets while accelerating then it is bad.

 

There is a known issue with the '03 throwing p0300 codes. There are several TSBs out for this issue so the dealers are aware of the problem.

 

That's good to know but a lot of the threads I saw indicated that the fixes often did not work. Also how does the dealer work with a modded car? Most importantly is the fix free

 

the light was on already when I first got into the car. The owner said it came on during a lapping day at the track

 

So I take it you just bought the car. I would of been alittle worried if I bought a used car and it had the check engine light on and the owner raced the car.

 

I have yet to purchase the car which is why I came here to ask for advice since I am worried .

 

P0300 codes are very common especially in the 03's it's nothing much really just a sensitive sensor in the drivetrain causing it to trigger. The car will run fine. What causes the sensor to trigger has been reported as simple as a clutch install, the transmission with a straight pipe and some even report the input shaft. in either case it's not something worth getting worried about. It is normal in the Evo community.

 

So is the consensus that this should only happen while crusing cause I doubt he was crusing at the track

 

does the car have violent vibrations in 5th gear???

 

change the spark plugs...