I got a road tune in the summer for my mods listed. It was all good untill the weather has been colder. The idle was set for 1000rpm. Now that the weather got colder the idle surges most of the time between 950 and 1500. Sometimes it will go to 1800rpm. Every once in a while it will idle normal but havent associated with anything. This is with the engine warm and in closed loop. I looked for a vacuum leak but couldent find one. My Evo only has 16k miles on it so I dont think its the o2 sensor. The main question is could this be a tuning issue since it was tuned in the summer or should I be looking into something different? Any help or pointers would . Thanks in advance

 

Anyone have any ideas?

 

Still looking for an answer

 

You get 0507 SES?

Check vac lines:
Manifold to PVC check valve
line that goes to MAF to turbo pipe
two egr lines to the solenoid (top of TB)
fat line on top of manifold to purge sol
fat line to master cyl
FP lines (hope not)
any other vac leaks

If that is good then check stepper (7mm socket) for any signs of damage

If that's good then I could write more but were not half way through the list so check back

 

I dont have any codes stored or a check engine light on. I checked all vacuum lines for leaks visually and with a can of brake cleaner. I checked the vacuum line all the way back to the charcoal canister also. I havent checked to see if maybe the pcv valve is possibley frozen open. Not sure if this would be considered a vacuum leak . Not sure what you mean by stepper. If you are refering to the idle valve then no I havent checked it

 

you can adjust your idle on the back of the throttle body. theres a philips head screw you can adjust it. do you always let the car warm up properly before driving it??

 

I warm it up as the manual says which says to wait till the temp needle starts moving. I will try to adjust the idle but it is surging not just a high idle

 

ahh i see. well still just try adjusting it and see what happens. if that doesnt work then let me know cuz i have a buddy that works for mitsu

 

I still think its a tuning issue but have no way to prove it.

 

it could very well be. whod you get it tuned by?? call them up and explain whats going on with your ride and they might be able to help you out.

 

It was tuned buy no one famous. I did talk to him and he said it probably isnt the tune. The idle was fine all summer but since its been cold the idle has been this way

 

Have you cleaned your throttle body? Mine was dirty and would not close properly...problem solved.
Mine was jump to 2500 rpm and would fluctuate even when I let the car properly warm up and even after driving for a while.

 

I only have 18k miles so I dont think it could be dirty but that is one more thing to check

 

you would be surprised. The UICP side was spotless, but the intake side...was black as night. and I only drive it on weekends and nice weather.

 

So as of now I will clean the throttle body and try to adjust the idle