I've been having horrible machinegun-like misfires ever since my last round of mods went in. I have *never* gotten a CEL before these misfires. Anyway here's what I had before the misfires started happening:

• stock turbo
• stock airbox
  
• stock filter
  
• stock DV
• stock headbolts
• 272i/264e cams
  
• Vishnu gears @ -2/-2
  
• 3" Vishnu TBE
  
• 3" UR testpipe
• XEDE
• Walbro 255 pump
  

Here's what I added all at once (well over a week period, but I never drove the car during that time):

• White Rabbit
  
• Denso 660s
  
• K&N drop-in
  
• Forge DV
  
• XEDEflash w/ injector scaling
  

I drove the car for a little over a week (maybe 100 miles total) untuned with a zeroed out XEDE map. Misfires all over the place. I thought it was from not being tuned, so I didn't worry about it. TurboTrix came down and I got a road tune. Car performed flawlessly during the tune and right after it. It was 90 out during the tune, so its not like the weather changed much since then (been +/- 5 deg). Misfires started up again pretty much the next day. I have since switched back the stock DV, checked all clamps for leaks, changed plugs 3 times (currently on BR8ES w/ 024 grap) with down to 022 gap, thoroughly checked wires and coil packs, tightened down vacuum lines on back of intake manifold, inspected injectors, added/removed fuel with the XEDE and finally ran some xylene (in case gas was bad). Car has only 8400 miles on it. Makes perfect boost (up to 22lbs tappering to 19) and vacuum. Plugs have always looked perfect when pulled. All codes that I've gotten pulled have been P0300s (but given there have been plenty more I've just cleared with the battery). Here are the symptoms (that happen most of the time):

• I can cleanly pull thru 3rd gear from a stop at WOT, but get the misfire and code in the middle of 4th gear.
  
• I get the misfire and code if I'm at a low rpm in 4th gear, then hold the boost at 5psi.
  
• I get the misfire and code if I floor it on the highway more than than a few seconds in either 4th or 5th gear.
  
• I get the misfire and code randomly in low gears at low rpm at low throttle position.
  
• Pulls in 4th and 5th gear are not clean, feels like there is a slight hesitation when it doesn't misfire.
  

Hmmm I think that about covers it. I don't have a wideband so I can't check AFRs, but I was tuned to the mid 11s. What do bad injectors and/or bad fuel pump cause symptom-wise?

 

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I wonder if SMART would help? I have no idea though. With my WR and XEDE with SMART I have no problems except a stutter once in a while when I lift off the gas while cruising in 5th or 6th. Ask Shiv maybe?

 

I have SMART coming, I really hope it will be able to automagically fix my problem.

 

There seems to be an under lying issue with the tune... I had all of these problems up to getting rid of the Xede flash and having Mark just flash the car with my Xede only modifying boost. Why didn't you call me with these problems? Or better yet, call Mark. You would be a fool not to go to the source! My car now drives flawlessly. I'm sure there is additional power left on the table, but I'm just enjoying the car right now, and not worrying about tweaking it out.

I intend to run Smart also... on top of my flash. However, in the world of automobiles, nothing "automagically" gets fixed... You might inadvertently fix the problem, but you have to fix the problem nonetheless.

 

Mark did remove my XEDEflash. He did all the fuel tuning direct on my ECU, then did timing on the XEDE. And as stated earlier I didn't think I had an issue (in my mind) before I went to the tune.

 

Call Mark! I don't know why he didn't just do yours just like mine... other than me telling him that was how I wanted it done.

 

Cause I told him I'd rather have most of the tune on the XEDE than a simple reflash. Anyway how is Mark going to fix the problem I had *before* his tune? I'll talk to him nonetheless. The point to this thread was to see if anyone else has had issues like this and could shead some light. Still trying to figure out what a faulty injector would feel like.

(I do appreciate you trying to help, don't take my comments above the wrong way)

 

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I was in the same situation as you last year. I had a custom Dynoflash and asked Shiv to try and tune on top of it to squeeze out every last bit of power.

The result: Misfires.

My car had NEVER had any misfirings before. Took off the Xede, and no more misfires.

The way I see it, you have 2 choices. Simply use the Xede w/ a stock or MILDLY modified ECU, or dump the Xede and go with a full flash.

 

I had the misfires with a zeroed out XEDE and a stock ECU with just XEDEflash (which I've run for months with no issues) on it. I really don't think its an issue of the XEDE interferring with the ECU.

 

Really? Did you ever try to actually DISCONNECT the Xede when this was happening?

 

My misfires (P0300 codes) started when I was still stock. They're still going on after flash. Aggravating as hell and no clear solution.

 

The only mods on my evo is an HKS cat back and RMR intake and I had the local dealership "reflash" the ecu to fix the damn p0300 code. Unfortunately after about every 300miles im still getting p0300 codes.......Im getting tired of having to reset the damn ECU and the dealership is insisting that my mods could be the reason.....I'll be putting back the stock intake this weekend, hopefully the BS will stop.!!!!

 

I no longer have the boost pill, so if I disconnect the XEDE I won't have any boost control. Regardless I've had an XEDE for a year now and have not had a single CEL until this misfiring crap started.