Hello All,

2002 A4 1.8T...Blanca. Ran very well until...
last month I lost heat completely... 2weeks ago she started ideling rough and misfiring. now getting less than 250 miles on a full tank 15-16 MPG!

At idle the CEL flashed at me and I drove to the nearest shop. Dealership!
Diagnosed misfire in cyl 3 and intermitant misfires that seemed to move around. 3rd cyl consistantly. checked coils, were OK. replaced spark plugs...still misfiring. advised me to change injector in cyl 3 only...$400.

Blanca is APR tuned Stage 1. I purchased 4 TT225 injectors and reflashed to Stage 1+...$380. Blanca still misfires. disconnected MAF, no difference. looked for vacuum leaks, none visible.

Prior to loss of heat.
-blew coolant hose while driving and car shut down.
-replaced hose & CTS (green one)
-fan blowing immediately when car starts...it's been below 20 degrees much of the month. battery dead each morning.
-replaced battery

Any ideas on what could be wrong?

 

coil harness

 

Thanks petzl. You sound sure.
Found major leaking Breather hose, replaced... also replaced pancake valve and pump/valve on PCV system. Still misfire. The RPM when idling stays flat yet I hear the misfire. the car bogs below 3k RPM. Seems to open open up well beyond 3k RPM. Gas mileage is less than 12 MPG...was getting 22 to 26 MPG.

 

rabbit , did you find a resolution to this issue...?