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Idle and throttle tip in misfire only

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Hello guys,its been 3 weeks im having that weird idle misfire in my evo when tipping in your foot on the throttle you can feel it my afr at idle are not stable anymore they go to 12 then jump to 17 and back to 15 every 15 to 20 seconds i checked for boost and vacuum leaks NONE!changed plugs this thing is annoying my afr when cruising are perfect and at wot it drives fine sometimes and sometimes it has a small miss at about 4 k rpm

No new mods or tune changes also i realised that at idle i cant rev the engine with an instant wot but if i go smoothly it will rev to redline

Does it fell like a bad MAF sensor ?

Thank for your help

what ecu are u using? if stock what are the low and mid fuel trims (LTFT)? are u on aftermarket injectors?

Im on stock ecu stock injectors for now looking to solve my problem then advance to aftermarket injectors and cams as for the trims im waiting for the evoscan software and tactrix cable to arrive so i can check the trims and the actual values of the sensors i ordered them a week ago

You need to have a little more data so that we can help you. Once you have your cable and evoscan, make some logs and upload them. The fuel trims will tell a lot about what is going on.

Thank you andre will update with my logs once evoscan is ready!

want to bump this as im still facing this issue randomly runs fine for some weeks then gets back for small misfire at idle, and some breakups on wot sometimes,when they happen they last until i decrease boost pressure for less then 20 psi logs attached but these pulls had no breakups whatsoever

Attached Files

this is an idle log where i went WOT at then end of log and car wanted to stall,Afr's at idle dump into 11 and 12 for a second then back to normal

Attached Files

So let me make sure I am following you. There are possibly some conflicting information here.

1. Runs fine for weeks and then out of no where breaks up on a wot pull at 20+ psi

2. After pull will misfire at idle, and run rich... (Misfires at idle will show a lean condition on a wideband as you are introducing unburnt mixture into the exhaust stream) Sounds like a rich after wot pull which is a tuning tweak and its not really a misfire...

3. Car will continue to misfire until you lower boost to

1 is true

2-no car can be misfiring on idle and pulling good the misfire is just at throttle tip in its not dependent with the break up

3-yeah car will continue to break up on WOT until lowering boost to 19-20 Psi

my post was incomplete lol

What plugs, gap and ignition are you running?

maybe when we could find a time for both of us i can team viewer in, specifically when its happening if at all possible.

I tried swapping 3 sets of plugs with different gaps all brand new problem was still the same.Yeah that would be great anytime your free just let me know

As for ignition im running stock coils and wires

Ok, I see what you are talking about on log20.06.23.

I think one has nothing to do with the other as far as WOT and Idle. Kind of inconclusive data however. You still haven't mentioned what plugs and gap you are using. Which 99% doesn't have anything to do with your idle issue however may reflect you wot problem over 21psi.

Now that I think about it, stick your stock map sensor back in. Those Omni whatevers are freaking junk. I'll bet money your random idle issue lies there now that I look again

That is your issue. Its flat lining. It isn't wiring or any other nonsense, the sensor is a total POS!!!!!!!!!

Stick your stock map in and don't worry about the map being out of range for now. Once your satisfied your fixed buy your self a couple of lab grade sensors such as SSI technologies, RaceGrade or let me know and I'll send you some. Map and Fuel Pressure to start. I would consider a extra absolute for Emap since your guaranteed to be running stupid high back pressure being your a small motor. Oil pressure for warm and fuzzies isn't a shabby idea either.

Your WOT may be the same issue but unlikely. Even if it was you probably cannot log at a fast enough rate to see it. But one thing at a time.

Actually i dont have my stock map sensor as i bought the car with the omni on it.im on a maf setup i thought for a while it can be the MAF causing the idle issues as its reading rich which is commong with a MAF setup.ill try searching the lab grade sensors to see if i can ship one to my country

Thanks a lot man really appreciate ur help

Stock gap on plugs on car right now.Should i go down to 0.022"?

Dude.... Are you running stock plugs also?

I do not know enough about Lebanon and its laws for import/export. Actually, I must apologize, I know basically nothing. I'm just a overpriveledged lazy American lol.

Is there part availability for your evo within the country? If not and you can easily have products shipped in let me know and i will do my best to help.

Haha no prob my friend the only sensor i can sort oit is a replacement omni 4 bar as thats the only sensor evos use here locally .Shipping a sensor can cost as much of an engine here LOL so i will swap out with an omni.As for plugs BPR8ES NGK gapped to 0.55mm

Update! it was the MAF sensor causing all the issues

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