1.8t Missfire & Heating Issues

[Danchan]

Hi Everybody,

I am new to the forum, only found it when searching for answers to my current problems on the internet.

I am having a few issues as the thread title suggests. When idleing the revs are all over the place although when the car had a service recently (included new plugs) nothing was shown on the diagnostics, any body know whats causing this, seen some mention of a coil pack on the forum could this be the problem?

To make matters worse there now appears to be a problem with the heating / cooling system, the coolant warning light flashed up, when I checked it the coolant level was fine, now a couple of days later the blowers in the car are blowing hot then cold then hot again even when the air con is switched on? Has anybody got any ideas why this could be happening??

Thanks,

Dan

[MickCheese]

Had the same problem recently with mine. I removed the MAF sensor and gave it a good clean with carb cleaner even though it looked potless and have had no problems since.

You could try that as it is free other than a can of Carb Cleaner.

Your heating issues may be linked to a problem thermostat or an air lock?

Good luck

Mick

[jez24oo]

i once had a problem like this my car then a golf 1.6 it would cut out at the lights and have poor acceleration just after a service the problem was one of the mechanics had put on an air intake pipe on upside down or the wrongway round or somthing any how to cut along story short it could be just the same problem ie poorly reconnected pipe

[Crasher]

The first thing to do is have a fault code read done. What year and engine code?

[Danchan]

Thanks for the responses guys,

Beginning to think the heater issue is down to a faulty thermostat as noticed yesterday that the temp gauge in the car is up and down also, so will try that first.

I'll also try cleaning out the MAF sensor.

The Engine code is AUG I think, although when it was plugged in it didn't detect a fault?

Will let you know how I get on,

Dan

[Crasher]

Does the heater get hot if the car is stationary but you keep the revs up at around 2K for a while but go cold if it is idling or if you are driving? I have had a few AUG engine with stuck open thermostats and it makes the heater go cold and causes the engine to over fuel.

[Danchan]

Hi,

Are you saying that the thermostat could also be causing the missfiring issue??

It seems to be quite random to be honest, when idleing or driving the heater blows hot and cold. Going to replace the thermostat in any case as it sounds like the most likely cause, will also drain and flush the system at the same time.

Thanks,

Dan

[Crasher]

If the engine is over cooled by a stuck open thermostat it can over fuel and cause a misfire.

[Danchan]

Thanks Crasher, will change the thermostat at the weekend.

Just had another thought reading some other posts, the battery went completely flat (left interior light on over weekend!) around about the time the missfire / idleing issues started, any chance that has anything to do with it? Thought i'd mention it as somebody else on the A4 forum had similar issues after a dead battery?

Thanks,

Dan

[Crasher]

It will need a throttle body clean and then a Basic Settings 04 group 098 reset using VAG-COM or similar.