As the title says, the car "hiccups" between 5,500-6,000 RPM and is normal after that. Doesn't pop codes or anything and no check engine. Driving observation also noted fuel consumption more than normal and occasional backfire. This is not on my EVO.

Before I start to dig further, I just wanted to ask if anyone here has had the same or a similar scenario before? If so, what did you find was the problem?

 

change your spark plugs

 

Check the plugs. Easy and cheap fix.

 

delete

 

We did, and we also changed them. Still the problem exists.

 

Gapped?

 

The platinum plugs don't require gapping, and Mitsu service manual doesn't recommend it, unless there is something different out there

 

I always gap mine. I was told to always check the gaps, regardless. I run the regular NGK's and change em every oil change. GL.

 

bad tune? that could be knock a messing with the timming to make it hickup like that

 

i had the exact same problem then i re gapped them to .024 and it fixed the missfire

 

+1 and platinum plugs suck.. regular ol NGK's is the way to go... unless ur an 8sec beast or something

 

I run NGKBPR7's every oil change and gap down to .20. I used to have similar problem until I gapped the plugs down. I am running more boost and timing and this helped me. It sounds like you could need a tune too to make sure it isn't anything serious before you do any damage. Have you logged it?

 

your timing map may be terrible during that rpm cross point to load.

 

Thanks guys. I'm usually up on things, but today was one of those days and I wasn't wearing my einstein wig

I'll do the easiest first, and I'll gap them to try to get the misfire out. If that doesn't work, I'll buy the normal plugs and take the recommended gap from SpooksEvo and localstoy73. I am sure somewhere between the two gaps, there is the sweet spot..

Datalogging... I know of one person over here who can do this, and he is a friend of the owner of this particular EVO, and I'll ask the owner to bring him over and we'll do a datalog day. There's another EVO VII that has had this problem, as well, so I have heard. May as well make it worth everybody's time. Me and mine (bone stock with a few bolt-ons; I like to keep the daily driver thing for a while)? I don't have these issues, thank God, but these are definite lesson points.

Yes, I was thinking the timing map, but again, i don't have that capability yet, but I see myself heading in that direction really quickly. I am just a wrench-turner/part-time racer with enough knowledge to be dangerous, but smart enough to know when to ask for help.

Thanks again, guys, and I will post back with my findings very soon.

 

I had this exact problem changed my fuel pump and its all better..!!