engine light and poor idle when cold!

chompy_snake · 27th December 2015, 14:34

This seems to be an issue that is progressing with my Zt 160 v6 as the weather gets colder and wetter.
All of this started with a lumpy idle when cold. Quickly this has progressed to an exhaust rattle/blowing type noise up at the front at certain revs. To top all that off when the engine is below 1/2 gauge temperature, the engine seems to lack power, rattles from the exhaust when driven up to speed and the engine management light will come on if you accelerate at all briskly to 40mph and start flashing! The light goes out when you stop acceleration and then doesn't come back on until cold again.
I was thinking a cat failure as a possible. I only reach this conclusion as the previous owner had a plug blow out and drove from Manchester train station to barrow in furness on 5 cylinders.
I have had the car on a generic reader, no codes are showing so left a little confused.
Any help greatly appreciated on this matter, also to note is the fact I lose maybe a quarter pint of coolant per week to no obvious cause and have recently replaced the expansion cap and a radiator hose but still losing a little coolant.

Thanks Graham

kaiser · 27th December 2015, 16:12

Leaking inlet manifold gaskets, especially if also loosing water.
Spark plugs, if old they can set the engine light on.
Ignition coils.
Fuel pump housing coming undone/filter dirty.

These would be my first points of call.

chompy_snake · 27th December 2015, 17:33

I will take a look at the inlet gaskets first I think, at least I know they are easy to get.
Then move on to the plugs ... I wasn't even aware that they had a water feed into the inlet as on the K4 engines.

Would the inlet gaskets stain the top of the V all weird and brown?, mine is badly stained but has no standing water there. I can smell hot coolant sometimes on the gearbox side sometimes too.

Already checked the guide on how to change rear plugs so will do those at the same time as the gaskets! Thanks for the list of things to check, my first KV6 car so it's a bit of a learning curve

27th December 2015, 14:34	#1
chompy_snake Newbie Mg ZT Join Date: Nov 2015 Location: Thornaby Posts: 27 Thanks: 7 Thanked 2 Times in 2 Posts	engine light and poor idle when cold! This seems to be an issue that is progressing with my Zt 160 v6 as the weather gets colder and wetter. All of this started with a lumpy idle when cold. Quickly this has progressed to an exhaust rattle/blowing type noise up at the front at certain revs. To top all that off when the engine is below 1/2 gauge temperature, the engine seems to lack power, rattles from the exhaust when driven up to speed and the engine management light will come on if you accelerate at all briskly to 40mph and start flashing! The light goes out when you stop acceleration and then doesn't come back on until cold again. I was thinking a cat failure as a possible. I only reach this conclusion as the previous owner had a plug blow out and drove from Manchester train station to barrow in furness on 5 cylinders. I have had the car on a generic reader, no codes are showing so left a little confused. Any help greatly appreciated on this matter, also to note is the fact I lose maybe a quarter pint of coolant per week to no obvious cause and have recently replaced the expansion cap and a radiator hose but still losing a little coolant. Thanks Graham

27th December 2015, 16:12	#2
kaiser This is my second home 75 Tourer 2.5 Auto, 1.8T, 75V8ZT Join Date: Jun 2007 Location: Johannesburg ZA Posts: 6,200 Thanks: 1 Thanked 859 Times in 613 Posts	Leaking inlet manifold gaskets, especially if also loosing water. Spark plugs, if old they can set the engine light on. Ignition coils. Fuel pump housing coming undone/filter dirty. These would be my first points of call. __________________ Worth his V8 in gold

27th December 2015, 17:33	#3
chompy_snake Newbie Mg ZT Join Date: Nov 2015 Location: Thornaby Posts: 27 Thanks: 7 Thanked 2 Times in 2 Posts	I will take a look at the inlet gaskets first I think, at least I know they are easy to get. Then move on to the plugs ... I wasn't even aware that they had a water feed into the inlet as on the K4 engines. Would the inlet gaskets stain the top of the V all weird and brown?, mine is badly stained but has no standing water there. I can smell hot coolant sometimes on the gearbox side sometimes too. Already checked the guide on how to change rear plugs so will do those at the same time as the gaskets! Thanks for the list of things to check, my first KV6 car so it's a bit of a learning curve