Hi all.

Could this be a vacuum leak

Hissing sound when in drive sounds like coming from drivers side, brakes are spongy too unless you compress a few times then they are OK. Then today started miss firing, stuck the torque app on it and came up with P0308 cylinder 8 misfire could they be all related?

Thanks in advance

 

Yes vacuum leak. Sounds like brake booster. With the miss fire on only one cylinder I would think maybe time for plugs or a bad coil pack. IMO fix the vacuum leak first, clear the code see if it comes back.

 

Thanks so much p38251 really appreciate your input ill get onto it tomorrow

 

Can i ask how i would go about checking the vacuum leak on the brake booster please

 

This might help
http://www.agcoauto.com/content/news/p2_articleid/129

 

Check the vacuum lines that pass under the drivers side closest to the exhaust. They tend to dry up and crack over the years. I had a few go bad on mine...

I would hear the leak every time I turned the engine off... I would hear a slight leaking sound underneath the truck...

Good Luck and please keep everyone posted.

SPEED SAFE, NICK