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Discussion Starter · #1 ·
It all first started about 3 weeks ago...every morning when the car was started completely cold it would start a little hard then misfire for about 30 seconds then run AND start fine the rest of the day. When it was doing this i had multiple spark plug misfire codes on VAG-COM and figured i'd change the plugs soon. Now the car doesn't start hard anymore or misfire when first started but every few days when i come to idle at a traffic light the RPM's will drop really low (down to about 500) then back up a little then stall but it starts right back up then runs fine. Since its been doing that there are no misfire codes. i've change most of my vacuum lines to silicone already (except the SAI ones) and i checked my TB hose to make sure it was secure etc. so what could be the problem??? is it a fuel flow problem??? my car is an 01 1.8t and i have 60K on it....i replaced the MAF about 6 months ago and last night i logged up to 161g/s at 5200RPMs so that seems fine too......HELP please!!!
 

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Discussion Starter · #3 ·
cool that'd be helpful :)
 

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My car had the same type of symptoms. I had just changed my plugs. Idle would go real low and then bounce back up. A few days later my ICM went bad. May have been a coincedence but after replacing the ICM idle was fine.
 

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Discussion Starter · #7 ·
throttle body is clean (just cleaned it about 2K ago) also i just had my big timing belt change done............why would the temp sensor cause that???
 

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B5veedub said:
throttle body is clean (just cleaned it about 2K ago) also i just had my big timing belt change done............why would the temp sensor cause that???
Oh! Actually I think that was the answer to my idling problems - flushing the throttle. So I dont know what else it can be.
 

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Check the grounding! Is the idle worse with the AC on?

I just fixed the same dipping idle symptoms on my car and on my car anyway the cause was an electrical grounding issue (which is why there were no error codes showing bad components or sensors).

In any case, check your grounds. First, disconnect the battery and clean the terminal posts and the cable connects with sandpaper or steel wool. If your battery is old or crappy (especially if it is crappy VW OE), replace it. Next check the cable that goes from the negative battery terminal to the ground point to the chassis at the bottom of the battery compartment. Clean that connection point, too, and replace the negative battery cable to it if it looks iffy. If that doesn't help, keep going...add a ground strap from the battery/chassis ground to the block. An 18" 4AWG Ancor marine-grade tinned copper 'battery cable' from West Marine is perfect, you can connect the block to the ground point with that.
 

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Discussion Starter · #10 ·
interesting i may have to try the battery thing. My car never showed any other problems with the battery though and at first i did have misfires. Now the car just has a shaky idle sometimes and one correction to my original post is that the car does still start hard when the engine is cold.
 
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