Hi, i have a Mk4 Golf 1.8T that is suffering from a misfire some of the time. It occurs at startup 95% of the time (Has done it twice when driving from cold). When it occurs the car only fires on what seems like 2 or 3 cylinders. It is possible to keep the engine running, and if i do so for 20-30 seconds, the misfire goes away. I have had 2 breathers changed as they were found to be faulty (holes in both). Althought this seemed to sort the problem it has not gone away. I have changed the plugs but this has not solved the problem. I plan to clean the throttle body thoroughly. It has had a little clean and been readapted upto now. I have the VAGCOM diagnostic results also; 17608 - Boost Pressure Control Valve (N249): Mechanical Malfunction P1200 - 35-00 - 16795 - Secondary Air Injection System (B2) - Incorrect Flow or Secondary Air Injection System: Incorrect Flow Detected : P0411 16684 - Random Misfire Detected - Any Cylinder or Random/Multiple Cylinder Misfire Detected : P0300 16688 - Cylinder #4 - Misfire Detected or Cylinder 4 Misfire Detected : P0304 17705 - Pressure Drop between Turbo and Throttle Valve (check D.V.!) : P1297 16685 - Cylinder #1 - Misfire Detected or Cylinder 1 Misfire Detected : P0301 16687 - Cylinder #3 - Misfire Detected or Cylinder 3 Misfire Detected : P0303 17956 - Boost Pressure Regulation Valve (N75): Open Circuit : P1548 I have checked the functionallity of the Diverter Valve by disconnecting it and attempting to suck air through the 3mm tube. It seems to be functioning as i could not 'suck' air through it. Just wanted you guys to look at the VAGCOM results and add your 2p worth Cheers
how about faulty spark plugs maybe cracked? just a thought as mine was doing it and all was good sometimes then other times it wasnt, changed them and all is well, hope that helps
first id delete all the codes and drive around normally for a few days and then post up the fresh codes. common things to do with misfires: MAF (aka air mass meter), Coilpacks, Coilpack Harnes wiring some quick q's.. Does the misfire get worse when its wet? What gears does the misfire usually occur? Does it happen under load (when booting it..)? Luke
now then, the DTCs are new this week. the fault memory was wiped a week ago. it happens reguardless of the weather conditions. it happens in all gears but only when the engine is cold and only happens probably 1/5 times the car is started. its defo not the plugs as i changed them. just wondered if you guys have ever had the same faults and what you did to eliminate em. there may be numerous causes, and thy might not all be part of the same problem.
n75 valve? (controls turbo and wastegate) more unlikely concidering the simptons is the MAF. its unlikely to be coilpacks unless you have done 3 of them, and you'd expect it to be worse in the wet. have you looked at the wiring to the coilpacks? they can often carrode ect. Luke
i doubt its the coil packs as it had misfires on all 4 cylinders previously and it does not get worse in the wet
