Airtrek RPM issue

[skullx]

Hi guys,

Sorry for the long post.

As you may recall I had an issue with my Airtrek I posted here several months ago now where as around the time of replacing the intake for a pod filter, the engine only once at operating temperature would "hunt" between 1,700rpm and 2,000rpm when in that rev range (more noticeably when under load on an incline)

So pretty much in town driving at 50km it sounds like it is changing gears down and back up over and over, shuddering at times. Putting the car into tiptronic mode and keeping it in 4th gear makes no difference. Keeping the engine revs above 2000rpm and it's fine.

So far I have tried;
Disconnecting the battery to reset the ecu
Refitting the original airbox assembly
Checking all hoses and lines for leaks/loose connections
Trying a brand new aftermarket BOV
Cleaned all throttle body and intake pipes
Checked transmission oil level

I'm thinking it may be related to the MAF sensor as I damaged the Honeycomb grill when changing to the pod, I have since tried another second hand MAF I brought off the internet the grill turned out to still be damaged but no where near as bad as what I had done to my original one.

Any suggestions? Time to buy a brand new MAF sensor? Take it to the Garage?

Thanks Guys

 

[stutzedward]

I will not advise buying a used MAF. Get a new one and ensure it is Airtrek's and not Evo's cos they are slightly different.

Did you check if your idling control valve is ok?

Did you try adjusting the idling screw hear the throttle body facing the firewall? You have to do it with a very short screw driver.

 

[skullx]

Thanks Stutz,

I will look at getting a brand new MAF. Idle control valve seems to be okay, it doesn't actually look very old and I think it was replaced before I purchased the vehicle.

I will try the idle screw tomorrow. Is their a recommended idle rpm when the vehicle is warm?

Edit; There is a good chance the second hand MAF I brought was off an Evo

 

[stutzedward]

Idle adjustment when car is we running temperature is 850rpm. U cannot adjust when aircond kids in cos that automatically controlled by ecu. U can only adjust without aircond.

 

[skullx]

Thanks Stutz,

I did a little bit of reading, is this safe to do without turning the ICV sensor off first with Evo scan or is this completely different

 

[stutzedward]

Yes, we do it all the time. I sometimes adjust it myself or Ah Wah (our known mechanic) does it when engine is idling as usual. No worries. Make a mark of the original setting, then adjust it. You can always readjust back to original state. U don't need to disable anything.

 

[skullx]

Thanks,
I'll give it a go this afternoon, although it is idling when warm pretty much where it should be.
I should also mention I just had a 3" catback exhaust put on which has possibly made the issue slightly worse.

I'm thinking about spending the money and getting it re tuned.

 

[vr2turbo]

Idle adjustment when car is we running temperature is 850rpm. U cannot adjust when aircond kids in cos that automatically controlled by ecu. U can only adjust without aircond.

My VR FICD a bit cranky dy, so I tune with air con on to around 900rpm, then when air con cuts, is 1k plus. Cannot help as if tune low without air con, it vibrates when air con cuts in....

 

[skullx]

Adjusting the idle screw seems to have made no difference to the problem.

 

[stutzedward]

Sorry bro. Is the check engine lite on? Maybe MAF then.

 

[skullx]

Thanks for your help. No check engine light, would have made it easier if it was on
Still waiting for Mitsubishi to get me the price of a new MAF.

 

[stutzedward]

Do u have an OBD II reader? perhaps you can check the log.

 

[skullx]

I brought one of those cheap Bluetooth OBD II readers a few months back. Found zero codes unfortunately.

 

[skullx]

New MAF sensor on its way, $500NZD later.

 

[stutzedward]

I paid almost RM1400 for a new one 3 years back. About that price.