304 Manifold air leak?

[Warranty Void]

At steady light loads the engine seems to hesitate every so often, been told its most likely an air leak from the inlet manifold, does this sound right?
Not too keen on pulling the manifold if I don't have to but I want to get this sorted out.
I'm assuming that an air leak would be causing the oxy sensor to see a lean condition on cruise and the hesitation is where it's being over fueled?
There's a tiny oil leak under the thermostat housing so maybe it's time to do the gasket anyway. Sigh.

 

[ari666]

"spray around the gaps with WD40 and listen to the revs. if there is a leak itll suck the WD40 in and the revs will pick up."

thats what a few people have said, ive tried it a few times and never had the revs pick up, so yeah. unsure if it works or not.

 

[showbags]

At steady light loads the engine seems to hesitate every so often, been told its most likely an air leak from the inlet manifold, does this sound right?
Not too keen on pulling the manifold if I don't have to but I want to get this sorted out.
I'm assuming that an air leak would be causing the oxy sensor to see a lean condition on cruise and the hesitation is where it's being over fueled?
There's a tiny oil leak under the thermostat housing so maybe it's time to do the gasket anyway. Sigh.

Dirty or blocked injectors can cause this also. With a pair of pliers crimp off the return fuel line with the engine running, if revs pick up slightly or smooth out you need to replace injectors.

 

[Warranty Void]

OK, should have mentioned that I've gone through a few cans of start up spray trying to find it and so has the mechanic, and that it does it on both gas and petrol which both run off the delco (with some input from the gas computer for the gas injection)
Have been thinking maybe air leak could be around injectors.
Does anyone know a workshop in melb east with a smoke machine thing?

 

[50LTRv8]

Also, might be woth taking the throttle body off and check the gasket between it and the intake manifold. Also take a look at your IAC valve, I just had to replace mine as it was causing issues.

If you spray some stuff on it and the idle changes try a new oring first before replacing the valve as they are not cheap.

 

[Reaper]

Aero start ftw!

Reaper

 

[juiceie vh sle]

just take the manifold off and replace the gaskets. ACL make a rubber gasket kit which is heaps better then the original cork ones. the job will only take you half a day and thats taking it easy. also would be worth replacing the injector o-rings for piece of mind.

 

[Warranty Void]

Cheers guys, I guess I know what I'll be doing on the weekend.

 

[Darren_L]

manifold leaks usually affect idle quality more than hesitations on cruise. Does it have a smooth idle or does it idle rough ?
I guess if you can't find anything else obvious, then there's no harm in replacing the intake gasket - process of elimination.

But if it were me, first thing I'd be looking at is ignition (ie leads/plugs/coil/distributor cap) and injectors.

 

[doigs8]

OK, my recommendation is that you take a die grinder and grind away everything until only the inlet manifold is left. Then you may see the problem. That is the same smart arse response that you gave me when i asked a genuine question on this forum. What a goose!