JMIG118

Hey guy when my ls430 is all cold you can feel the car idle a tad rough nothing out of the control, but you can feel it. It start up at 1500rpm. after a few 3 mins it at opt temp. and the rpm drop to 700 or 800 rpm. At this point with the car in park with/o the ac on there is a sighlt bump I can feel once evey 25 seconds... can this be a misfire or bad spark plug/wire? timing belt? or just normal?? There are no check eng lights or error codes, 83 k 02 LS430

maximussp

I feel it too int he mornings. Not worried about it.

junjdm

its just warming up....

croatone

Normal. My 01 ls430 does it as well. No engine is without harmonic vibration for the most part. I notice it is smoother when I run mobile 1.

JMIG118

Cool. but how about when all warmed up? I do feel a lil bump or misfire every 20/25 seconds when the car is in park??

BNR34

iTrader: (1)

My LS430 had the exact same symptom as yours, idle a tad rough with a bump every 25 seconds, EXACTLY how you described it.

Then I ran a bottle of Redline SI-1 Complete Fuel System Cleaner, after 1 tank of gas, that roughness and that bump is GONE!! It idle totally smooth now, I was totally amazed the dramatic difference it made! Now I did nothing else to the car except that, so it had to be the fuel injectors was dirty or something.

http://www.redlineoil.com/products_fueladditives.asp

I know this totally sounds like a sales pitch, but I don't work for redline or anything like that, it was just an amazing experience I had, now believe it or not, is up to you.

Now if any of you guy's LS430 have the same roughness now and decide to try a Fuel System Cleaner and if it does smooth out the idle, please report back your result. I want to know if my experience was just a coincident or if that Fuel System Cleaner was really that effective.

I used that same Fuel System Cleaner in all of my previous cars and never felt a differences in how the car behave afterward, so I am a bit skeptical, but this time the differences was loud and clear. So I want to know if it work for other people's car.