At light cruising with no load between 3800-4500rpm I get the Check Engine Service light on, with the error "Random missfire", the sparkplugs are ok, under boost even at 25-26psi the engine sounds good.
Just before the CEL light turns on at light cruising the engine rattles a bit and sounds like you drop small pieces of rocks on the road, but the sound is almost unnoticeable, you must listen very careful to hear it...
What can cause this problem ? I really don't know what to check anymore, everything seems to be ok.

I can post the timing and fuel tables if needed.

Thanks !

 

how can I delete this second post ?

 

I would rather see a datalog of it occuring but the maps might help identify your problem. There are occurances that have been tied back to a transmission vibration, obviously no amount of ECU tuning will fix this unless the code can be patched.

Here is the thread I was referring to.
https://www.evolutionm.net/forums/sh...ighlight=P0300

If you can post logs and screenshots of your maps there we can take a look and see if the tuning could play a part. Describing sounds across the internet is always difficult. Ping and detonation sounds like marbles on tin foil, is that what your hearing?

 

Thanks !
I think it's the transmission, because the gearbox makes a very loud noise and rattles in first gear when you start it slowly or runing in the reverse gear, but I did not know that the ECU sees a missfire when the transmission vibrates...

 

just my 2 cents.... i have an 03 Evo 8, and way back when I was running my stock ECU, I had the same code thrown. I had the code cleared and it seemed to not happen again. From what I have heard/ read, there was a TSB out for this and Mitsu may have an update. If your car is stock, bring it in and see if they can reprogram it from you.
My insurance is with Progressive, and they've provided me with recalls and TSB's for my vehicle. Here is the list below. Hope this helps.
Resource Center > Your Vehicle Info > Mitsubishi Lancer Evolution TSBs
Your 2003 Mitsubishi Lancer Evolution

Last updated: 04/18/2007


1 of 16: ENGINE AND ENGINE COOLING:ENGINE

Bulletin Date: MAR 2007
COOLING FAN CONTROLLER. ( NHTSA ITEM NUMBER - 10021349 )

2 of 16: ENGINE AND ENGINE COOLING:ENGINE

Bulletin Date: APR 2006
RANDOM MISFIRE (DTC P0300, P0301, P0C02, P0303, OR P0304). ( NHTSA ITEM NUMBER - 10019922 )

3 of 16: ENGINE AND ENGINE COOLING:ENGINE

Bulletin Date: DEC 2005
CYLINDER HEAD VALVE GUIDE AND VALVE STEM SPECIFICATIONS - SERVICE MANUAL REVISION. 2003 - 2006 LANCER EVOLUTION. ( NHTSA ITEM NUMBER - 10018798 )

4 of 16: VISIBILITY: DEFROSTER/ DEFOGGER SYSTEM: WINDSHIELD: CONTROLS/ WIRING

Bulletin Date: DEC 2005
HEATER TEMPERATURE DIAL HARD TO TURN. ( NHTSA ITEM NUMBER - 10006466 )

5 of 16: ENGINE AND ENGINE COOLING

Bulletin Date: JUN 2005
ROUGH IDLE/ MISFIRE. MITSUBISHI TECH TALK. ( NHTSA ITEM NUMBER - 10015626 )

6 of 16: STRUCTURE:BODY

Bulletin Date: JUN 2005
RECARO SEATBACK BOLSTER COVER (PART NUMBER CORRECTION). MITSUBISHI TECH TALK. ( NHTSA ITEM NUMBER - 10015631 )

7 of 16: ENGINE AND ENGINE COOLING:ENGINE

Bulletin Date: MAY 2005
CYLINDER HEAD HEIGHT SPECIFICATION - SERVICE MANUAL REVISION. ( NHTSA ITEM NUMBER - 10015821 )

8 of 16: ELECTRICAL SYSTEM

Bulletin Date: APR 2005
DIAGNOSTIC TROUBLE CODE (DTC) P0300 RESETTING AFTER REPROGRAMMING. MITSUBISHI TECH TALK. 2004 LANCER EVOLUTION INCLUDED. ( NHTSA ITEM NUMBER - 10015710 )

9 of 16: STRUCTURE:BODY

Bulletin Date: APR 2005
RECARO SEATBACK BOLSTER COVER BREAKAGE. MITSUBISHI TECH TALK. ( NHTSA ITEM NUMBER - 10015719 )

10 of 16: ELECTRICAL SYSTEM:ALTERNATOR/ GENERATOR/ REGULATOR

Bulletin Date: APR 2005
ALTERNATOR FR TERMINAL VOLTAGE - SERVICE MANUAL REVISION. ( NHTSA ITEM NUMBER - 10016133 )

11 of 16: ELECTRICAL SYSTEM:BATTERY

Bulletin Date: FEB 2005
BATTERY LOAD TEST RATE CHART - SERVICE MANUAL REVISION. ( NHTSA ITEM NUMBER - 10015337 )

12 of 16: SERVICE BRAKES, HYDRAULIC

Bulletin Date: JAN 2005
BRAKE BLEEDING PROCEDURES. ( NHTSA ITEM NUMBER - 10015217 )

13 of 16: SERVICE BRAKES, HYDRAULIC: FOUNDATION COMPONENTS: DISC: CALIPER

Bulletin Date: DEC 2004
CLEANING BREMBO BRAKE CALIPERS. MITSUBISHI TECH TALK. ( NHTSA ITEM NUMBER - 10018365 )

14 of 16: EQUIPMENT: OTHER: LABELS

Bulletin Date: DEC 2004
ORDERING FMVSS LABELS FOR SAFETY RECALL BULLETIN SR-04-005. MITSUBISHI TECH TALK. ( NHTSA ITEM NUMBER - 10018359 )

15 of 16: ELECTRICAL SYSTEM

Bulletin Date: MAY 2004
DTC P0300 CODE. ( NHTSA ITEM NUMBER - 10014353 )

16 of 16: STRUCTURE:BODY

Bulletin Date: MAY 2004
REAR DOOR JAMB PROTECTORS. ( NHTSA ITEM NUMBER - 10014363 )

 

4 of 16: VISIBILITY: DEFROSTER/ DEFOGGER SYSTEM: WINDSHIELD: CONTROLS/ WIRING

Bulletin Date: DEC 2005
HEATER TEMPERATURE DIAL HARD TO TURN. ( NHTSA ITEM NUMBER - 10006466 )

god i hate this one...

 

^^^^^^^^^^^hahahaha! me too!

 

did you figure out the problem cus my evo is doing the same thing. right now Im looking into fuel ratios and possible weak injectors. I am also upgrading the ignition system in a vane attempt to fix this as well. I paid for new stock coil when the car first starting popping the idiot light and thought my igniton was weak or i had a bad spring in the coil. I know of the recalls and that seems pretty legit and once I get back I will further look into that and if the transmission in the problem that would semi make sense. my light comes on almost certainly in 5th gear which irritates the hell outa me. hopefully we can find this problem. Ill keep you posted if you havent found it yet and tell you if i find whats wrong with mine

 

There is a TSB out for the 5th gear syncros. The '03 5speed throws our harmonics at the same frequency as what the knock sensor identifies as knock.

http://www-odi.nhtsa.dot.gov/cars/pr...pe=QuickSearch