Rough Idle on cold start-up on Audi A4 1.8T B8.5


Asked by Jul 27, 2019 at 01:45 AM about the 2013 Audi A4

Question type: Maintenance & Repair

Hello, I have a 2013 Audi A4 1.8T B 8.5 (petrol). During a cold start-up the
engine rough idles and sometimes shuts off. I have to rev it up a little until its
warm. Once it warms the problem goes away. I changed spark plugs, PCV
valve, HPFP but still have this problem. Any help will be greatly appreciated.

2 Answers


Problem Solved. So it was the thermostat that was faulty. Problem is that I did not address this problem on time, now with a faulty thermostat this causes the engine to run lean on a cold start, hence the rough idle. If this problem is not address on time (like mines) it causes misfires on all 4 cylinders hence stretching the timing chain. So now I also have to change the timing chain as well. If you ever have a problem like mines, please address it urgently otherwise it will end up costing you much more in the end.

1 people found this helpful.

thanks similar problem here... last week noticed my thermo housing was corroded and the mechanic fixed/changed it.... but now idling badly till warm... ? wonder if he did something wrong ? will get him to check it out again

Your Answer:

Audi A4 Experts

  • #1
  • #2
  • #3
    Josh Holder
View All

Find great deals from top-rated dealers


Related Models For Sale

Used BMW 3 Series
204 Great Deals out of 2,789 listings starting at $2,995
Used Audi A6
22 Great Deals out of 212 listings starting at $2,888
Used Audi A5
35 Great Deals out of 307 listings starting at $9,495
Used Mercedes-Benz C-Class
103 Great Deals out of 1,834 listings starting at $3,090
Used Audi S4
7 Great Deals out of 138 listings starting at $8,995
Used Audi A3
51 Great Deals out of 433 listings starting at $3,495
Used BMW 5 Series
48 Great Deals out of 703 listings starting at $2,966
Used Audi Q5
78 Great Deals out of 1,382 listings starting at $6,950
Used Honda Accord
55 Great Deals out of 2,017 listings starting at $1,995
Used Audi A7
10 Great Deals out of 149 listings starting at $17,990
Used Ford Mustang
43 Great Deals out of 1,827 listings starting at $5,750
Used Dodge Charger
52 Great Deals out of 927 listings starting at $4,900
Used Mercedes-Benz E-Class
53 Great Deals out of 847 listings starting at $4,998
Used Audi Q7
48 Great Deals out of 662 listings starting at $5,995
Used BMW 4 Series
65 Great Deals out of 655 listings starting at $17,888

Used Cars for Sale

2019 Audi A4 For Sale
5 Great Deals out of 112 listings starting at $34,888
2018 Audi A4 For Sale
66 listings starting at $26,995
2017 Audi A4 For Sale
25 Great Deals out of 175 listings starting at $20,900
2016 Audi A4 For Sale
12 Great Deals out of 125 listings starting at $17,400
2015 Audi A4 For Sale
17 Great Deals out of 152 listings starting at $14,499

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use. Content will be removed if CarGurus becomes aware that it violates our policies.