rattling and wierd symptoms

mudbug660 · March 10, 2007

Ok, first off my dad borrowed my truck to go on a trip and filled it up with 87 octane and I have a wester's 93/91 dual hot tune. it wasn't any towing or anything and he doesn't romp on it. Well while I was driving it around on that same tank later on, the engine started to have a slight tick.

You can mainly hear it when you crank it up and kneal down by the driver's door. If I pop the hood and try and hear it from the engine bay I don't hear it. The ticking doesn't go away after it warms up, it's always the same tone. Even after filling it with 93 octane a couple times it still does it. The performance was still the same so I didn't worry about it.

This started about 2 months ago and about a month ago it threw a cope and I checked it and it was p0420 (bank one low efficiency) which from what I've read is maybe the cat on the driver's side. But today on my way back from school when I would go to pass someone, I would floor it and it seemed like the engine's timing was being retarded BAD! It would go faster once it shifted back up. I'm not sure what the effects of the 87 octane would be or if it caused this. I wouldn't figure the cat would cause this but I'm stumped. 03' 5.3 sierrra

Thanks for any help. even opinions

ryank1 · March 11, 2007

Ok, first off my dad borrowed my truck to go on a trip and filled it up with 87 octane and I have a wester's 93/91 dual hot tune. it wasn't any towing or anything and he doesn't romp on it. Well while I was driving it around on that same tank later on, the engine started to have a slight tick.

You can mainly hear it when you crank it up and kneal down by the driver's door. If I pop the hood and try and hear it from the engine bay I don't hear it. The ticking doesn't go away after it warms up, it's always the same tone. Even after filling it with 93 octane a couple times it still does it. The performance was still the same so I didn't worry about it.

This started about 2 months ago and about a month ago it threw a cope and I checked it and it was p0420 (bank one low efficiency) which from what I've read is maybe the cat on the driver's side. But today on my way back from school when I would go to pass someone, I would floor it and it seemed like the engine's timing was being retarded BAD! It would go faster once it shifted back up. I'm not sure what the effects of the 87 octane would be or if it caused this. I wouldn't figure the cat would cause this but I'm stumped. 03' 5.3 sierrra

Thanks for any help. even opinions

Check for an exhaust leak before the cat which could cause the tick and the ses light.

mudbug660 · April 13, 2007

wil last weekend I raplaced my fuel filter, sparkplugs, and driver side exhaust manifold gasket and it still ran like crap. I took it to the dealership and and told them that it might be the cat because it was rattling when I would hit it with my hand. Well they replaced the cats and from what I heard it fixed it. I had to take my mom's truck back to school (Louisiana Tech) so I'll get to find out for sure Friday if it's fixed. The plugs showed that it was running lean. Any thoughts?