Alex2.7T

HI ,guys Im having some questions about a P0300 code I got on my 01 Audi A6 2.7t, I recently made a 10 hour round trip , and on my way back home at a stop light my car started shaking really bad from the engine while idle, I quickly turned the car off and moved aside, check everything was good and started car again, the problem was gone. But quickly realized that I haven't changed my sparkplugs for a long time(aprox. 2-3 years, I know Im really stupid for not replacing them in a long time).Car would still run but the engine vibrations could still be felt. Next day I tried to run to the autoparts store to get the plugs, but car was shaking even worst, so I just called my brother and went to get the plugs in his car. Replaced plugs, calibrated them to .032( thats what bentley manual says.), but I think others do them at .028, anyways replaced the plugs and car started good and ran good on that day. The next day took car to work, ran good early morning ,but when headind back from work, engine started shaking again, after that I finally got the check engine light to appear on the dashboard. Scanned car and got these codes(showed on picture), car has a rough start now, so now what Im thinking is that the coil packs need to be replaced or can it be something else?

tester123

What's the mileage? Clear all codes and scan Engine codes again.

If codes repeat, Check for Camshaft Position Sensors operation.

Possible but unlikely given the problem description, fuel pump is on its way ?... again, mileage??

johnkk

When the engine is idling roughly, disconnect plug from air mass meter. If engine smooths out, air mass meter is bad. If no change, I would suspect spark coils or cam sensors. Maybe spark control modules, but normally only one will fail so misses will be on one bank.

Harleyguy

Depending on sources, many suggest changing coil packs when you change plugs. Tester and Johnkk both have good suggestions that are inexpensive to try and may verywell solve your issue in short order.

jcman

Check for a vacuum leak, seems like 9 out 10 times it's the cause for a multiple misfire.

tester123

+1 on this as well. jcman, you might be the winner on this one!

Not 100% sure if that is the case with OP's issue but, after thinking a bit the CPS could (or should) set a code as well... and OP didn't mention that... so, it could very well be vacuum related.

jcman

The CPS will only throw two codes or none and act-up, usually it can cause problems hot after a running engine and rarely cold. After reading about all these parts the OP changed it would only seem logical on a vac leak.

4Driver4

Replace the coolant temp sensor before you do anything else.

Alex2.7T

Car has 105,000 miles , used to believe the fuel pump was the one failing, but I think it will be the last part im going to check. Might be replacing the coil packs and fuel filter first, car still has original coil packs,(maybe it was now time for a few of them to go out after this long trip) and believe the filter has never been replaced, too. Car starts normally and drives normally after the check engine light came on, only thing is that it just hesistates just a little when starting up the engine. If after this car still not good , will check for vacum leaks and the other sensors.

jcman

Water in gas around this time of the year is not uncommon depending on your location, but I think 4Driver4 has offered good advice too on a real cheap part to replace, $18 tops.