# 1999 A6 Hard starting..no codes or lights...ideas?



## Jfpetrick3 (Nov 1, 2010)

My 99 A6 2.8 quattro has recently begun to have extreme difficulting in starting cold. After several attempts, it seems that short-cycle ignition bursts over a several minute period eventually get it to catch-sputtering along the way-until I feather the pedal and get the rpms up for a short period. Once running, I have no issues the rest of the day. Only after sitting overnight or for extended (5-6 hours or more) periods of time. I have no codes or lights, run premium, and when this first showed up added injector/fuel system cleaner to the last few tanks. No change. Any ideas? Thanks! JP


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## imaudi6 (Aug 23, 2010)

Probably the coolant temp sensor. Its located behind the throttle body. Near the firewall. Its hard to locate, it has a four wire plug. If its a black sensor change it. The new sensors are green and less problematic. This is a cheap repair, just be careful when changing. There is a plastic clip that holds it in and they are easily broken. Good luck.


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