Polo 1.4 CLP - Misfire detected on VCDS but no codes

[luqies]

So when accelerating normally the car will misfire/hesitate and when the revs go higher it stops...however if i accelerate very slowly i can "dodge" the misfire.
So it only misfires when a certain load is on the car.

So I changed all my plugs and changed 2 older coil packs that had some corrosion. I also did injector cleaner. I will be doing a throttle body clean this weekend so I can rule that out as well...After all this ...still misfiring but car is driving better

so I did a VCDS scan and theres no fault codes...however when I did the advanced analysis it showed misfire on cyclinder 1 with no fault code...



any idea whats the issue?

mileage is only 130k

[Ashveer03]

Seems like a dirty injector..

A code is normally thrown when the misfire is continuous, ie: the misfire counter maxes out over a specific time. It maxes out around 256 or so then resets back to 0.

If possible try swapping injector 1 & 2 and check if the misfire counter follows the injector. Will give u a better indication of what's going on.

Sent from my CPH2371 using Tapatalk

[luqies]

Okay I’ll try that

I also forgot when I first did a scan on the engine after starting I had this code which didn’t show up on the auto scan

16711 - Knock Sensor 1 (G61): Signal too Low

But after clearing it car drove fine for a week. Then the misfires started again.

Also noticed twice on longer rides when I just drove without worrying about dodging the misfire the epc light came on. But switched off and on then went away.

Yeah ima do some troubleshooting this weekend and see

Is swapping injectors easy thing to do?

[Ashveer03]

Okay I’ll try that

I also forgot when I first did a scan on the engine after starting I had this code which didn’t show up on the auto scan

16711 - Knock Sensor 1 (G61): Signal too Low

But after clearing it car drove fine for a week. Then the misfires started again.

Also noticed twice on longer rides when I just drove without worrying about dodging the misfire the epc light came on. But switched off and on then went away.

Yeah ima do some troubleshooting this weekend and see

Is swapping injectors easy thing to do?

It's fairly straight forward, could require a few other items to be stripped out first. Not 100% sure on this specific engine.

That code is generally caused by a faulty knock sensor or wiring to it.
Check if it comes back again, worth having a look at.

Sent from my CPH2371 using Tapatalk

[luqies]

Cleaned out the fuel rail. Very dirty. Took out injectors and cleaned it with throttle body spray. Put back and all is well… for now

[luqies]

So today all the misfires came back. Cylinder 1 on hard acceleration… then also 2 but only when cyclinder 2 “overloaded”. Then at idle cylinder 4 misfires.

[luqies]

Issue was fuel pump. New fuel pump and all is well now

[luqies]

That’s why change your fuel filter regularly . Otherwise your fuel pump going to die early , like mine.