Manifold Leak Question

[tvr+bubblecar]

Would a small exhaust leak where the 4 pipes join cause misfire symptoms on light throttle ?.

I am going to fit ACT manifolds to replace my leaky ones and I am hoping they will cure my lumpy running on light throttle. All the ignition components have been changed which has improved things considerably but there is still an underlying misfire

Thoughts please

thanks
Chris

[Mutant Rat]

Unlikely.

It's possible that a leak could confuse the lambda sensor, which in turn would alter fuelling, but the misfire is much more likely to be ignition, or perhaps some other fuelling related issue.

[Wildfire]

Don't think so. I have a leaky manifold gasket and the car still ran fine aside from the annoying ticking sound coming from under the bonnet. Haven't driven it since it went, got the car home and left it, but I shouldn't think it would cause any issues.

P.S ACT manifolds are definitely worth it!! They look soo cool and access is much improved, espeically if you decat.

[tvr+bubblecar]

Thanks guys - I will check the inlet side for leaks which some other threads suggest. I am pretty sure the ignition is ok - Will still get the manifolds replaced

Chris

[griffter]

[quote=tvr+bubblecar]Would a small exhaust leak where the 4 pipes join cause misfire symptoms on light throttle ?.

Chris[/quote]

Have a look at / remove the vacuum advance (block the plenum end) and see if there's any improvement.