Air Filter Contributing To Low RPMs at Idle?

[desertkj]

I was running some errands tonight and at a few lights, I noticed that my tachometer was showing a frighteningly low figure. It was quivering between 500 and 600 RPMs at idle. I do know the air filter is EXTREMELY dirty and I need to get a new one. Could that cause such a low idle speed or am I looking at some more serious issues here?

 

[tjkj2002]

I was running some errands tonight and at a few lights, I noticed that my tachometer was showing a frighteningly low figure. It was quivering between 500 and 600 RPMs at idle. I do know the air filter is EXTREMELY dirty and I need to get a new one. Could that cause such a low idle speed or am I looking at some more serious issues here?

Yes and no,you may have a dirty IAC(Idle Air Control),it's part of the throttle body and controls the idle.

 

[_UnLiMiTeD_]

once its warmed up is it not supposed idle right around 600rpm or so? Thats where mine idles once its warmed up and when watching jeep liberty videos on here when it shows the tach thats where they are at when sitting and idling

 

[desertkj]

Mine has always idled around 750-800 RPMs. Tjkj2002, how hard is it to work on that IAC?

 

[MadDog]

My 06 3.7L always idles around 600 RPM once warmed up. I wouldn't think there's anything abnormal there. Was the vehicle vibrating or showing signs of stalling? If so, then you might have something to worry about, but if it was just idling low but running alright, then I would think you're fine.

 

[desertkj]

For the most part, it was running fine. The RPMs were slightly lower and I could watch the tach needle kinda vibrate. However, it never threatened to stall or anything. Also, it wasn't doing it today, so maybe it was just tempermental yesterday. I did use fuel from a station that I would typically avoid as well, so I think that could be partly to blame. I think I'm going to change the air filter, run some fuel injector cleaner through it, and refuel it with some Techron and see what it does before I worry about it any further.

 

[Bashgod]

I'm pretty sure 600 rpms in normal idle for most warmed up gas engines. I have a K&N filter and full Magnaflow cat back exhaust and mine idles steady at 600.

 

[_UnLiMiTeD_]

mine idles steady at 600 rpm also. Thats why i was confused when he said he was concered with it at that idle i was like huh? lol

 

[offrovering]

For the most part, it was running fine. The RPMs were slightly lower and I could watch the tach needle kinda vibrate. However, it never threatened to stall or anything. Also, it wasn't doing it today, so maybe it was just tempermental yesterday. I did use fuel from a station that I would typically avoid as well, so I think that could be partly to blame. I think I'm going to change the air filter, run some fuel injector cleaner through it, and refuel it with some Techron and see what it does before I worry about it any further.

unless it was dropping and jumping more than just vibrating, you are probably fine. 600 isnt bad, some run higher, but these seem to run fairly low just fine. i would bet its more to do with the poor fuel than IAC since it isnt jumping or stumbling, my thoughts

 

[MadDog]

I would also think that your RPM's are fine. Depending on how much mileage you have (if it's high), it probably is a good idea to change the air filter & run a bottle of Techron through the fuel system. Both are relatively cheap to do and will help with your performance as well. I highly recommend the Chevron Techron, it cleared up my injectors on my Camry really well after a not-so-great NYS emissions inspection. Gets better mileage too!

 

[_UnLiMiTeD_]

im thinkin maybe they had the idle set higher in 02 because the ppl that chimed it about idle being higher have 02's. I just had a full tune up on mine, air filter,pcv,spark plugs all new fluids in it and it still idles 600rpm when fully warmed up and its a smooth as butter

 

[tjkj2002]

Curb idle for all KJ's with the 3.7 V-6('02-'07) is 600-650 RPM when at operating temps(210-212 degress).