Rough Idle after head gasket replacement

[tommo295]

Hi Folks,

Just wanna say thanks for all the posts that have helped me up to this point, I always seem to find the answer to my questions through a post or two on here.

Now, to the point:

My head gasket failed after issues with a leaking radiator, there was no milky oil but I found water in the cylinders when I pulled it apart. After disassembly, I had the heads pressure tested and cleaned, and cleaned up the rest of the surfaces and gaskets as I went. After putting it all back together with new gaskets, it idles rough (particularly when braking), and a local mechanic said it was running on 5, so I changed the spark plugs, leads and fuel injectors just in case. I also tested for vacuum leaks with carby cleaner (mechanics suggestion) but seems to be all good.

The shop that cleaned the gaskets took the rockers off (I forgot) but didn't mark them. Not sure if that makes a difference.

Long story short, I changed:

Radiator
Head Gaskets
Head Bolts
Intake Manifold Gaskets
Plenum chamber gasket
Throttle Body Gasket
Transmission Gasket
Transmission Filter
Oil Filter
Air Filter
Oil
Coolant
Spark Plugs/Leads
Fuel Injectors
Water pump gasket
Accelerator cable (who the hell makes the thread out of plastic??)


It's running a bit better but definitely not how it was. I'm running out of idea's, so any idea's on what to check?


Thanks in advance

 

[jppcherokee]

While I had transmission done on my VT car was out of acton for about two weeks.
When put back together car was running on only five cylinders running very rough.
Zero codes were coming up on diagnostic.
I decarbonized plenum chamber and throttle body, cleaned injectors, new plugs coils leads, fuel and air filter, oxy sensors, oil and filter. Plugs fouled up bad.
Car ran a little bit better but then fell into a limp home mode where revs were limited, but would reset upon restarting.
I then changed the CAS.
That was the big culprit all along.
Runs awesome now.

I don't know if it will be an issue with your one but it was doing some weird things with my engine.
Perhaps worthy of some investigation

 

[Trevor 062]

may as well throw in a new set of coil packs, see if that helps

 

[Not_An_Abba_Fan]

The key thing that stands out to me is "particularly under braking", which points to a vacuum leak.

 

[edals]

Check the Vac hose that goes from under the throttle body, between the intake manifold to the back of it. The glue fails and no longer seal. Had this issue, 2 hose clamps solved it.