I tried doing a quick search, but most of the results led me to the X forums. I've got an '03 GSR with around 93k on it and not a problem to date until I installed my Optima Red top yesterday. I highly doubt the battery can cause a problem but it's worrying me. Basically, if I'm coasting and coming to a red light, if I clutch in and place the car in neutral the idle drops severely... down to about 550 and cuts off. This doesn't occur if I have my clutch in and the car in any gear. Don't know what's causing it but it just started happening this morning after I put in the Optima. Is it possible I knocked a hose lose somewhere? Car has some mild mods, but it is not cammed or anything like that and I'm still running the stock turbo and injectors etc. Any ideas? Thanks in advance.

EDIT: I forgot to mention the car seems to regularly idle too low, somewhere around 680-800. It tends to move around in that range.

 

Did you perform the 60k service? Did you do the timing belt job?

 

I've only had the car since about 88k but I changed the timing belt almost immediately after purchase. What entails the 60k service? (No Mitsu. dealers in my area)

 

Do boost leak test.

 

+1, sounds like a vacuum or major boost leak somewhere.

The Timing Belt/Water Pump/Balancer Belt/Serp Belts/Pullies is the big part of the 60k. I know they also recommend spark plugs, and a drivetrain flush.

 

Thanks for all the replies, guys. Doing a boost leak test with my homemade tester in the morning. I'll update when I finish.

 

Hey did you find the problems?????
I have the same problems recently.
Please let me know.
Thanks a lot

 

My '03 started dying when I put the clutch in and it turned out to be the ISC motor. The '03s apparently had a crappy design with plastic figers that they upgraded from '04 on. New ISC and the idle's rock solid again. Maybe you jiggled the ISC connector with the battery install? The ISC is on the underside of the throttle body, in the same neighborhood as the battery.

BTW, the part was ridiculously expensive, like $350 or so. The ISC motor failed on a Thursday and I couldn't take the stalling in stop and go traffic so I just had the dealer replace the motor. I decided that getting ripped off was worth the convenience of having a car that idled in bumper-to-bumper traffic!

Good luck!
-Franc

 

Hey Franc,
how you find out it is the ISC problem?
I just dont want to waste $350 for nothing.
Or do you know any problems will cause this issues?
It just happened one day when i was driving.
Also most of time it happen when it is raining.

Thanks,
Chris

 

let me know what you find out. i think i have a boost leak but cant test till this weekend. would like to see what you find out

 

sounds like an IAC... its located at the under side of the throttle body.