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2006 Grand Prix GT Misfire

For the cat temp I usually show about 900 or so and it can drop to about 500 idling and about 1200 when cruising. Ill check more on the drive home. I wouldn't think if was a problem at idle then it would be a huge problem at any cruising speed.

Jeff
 


Fivefingerdeathpunch said:
It's easier to just remove the front o2 sensor and do a pressure check. Anything past the converter means nothing, "back pressure" is a myth and is not needed on a vehicle like this.

The key thing isn't going to cause anything like this, the motor is still running so it's still working so it's not something where it's losing power.
Click to expand...

What are your thoughts about scavenging?

http://www.dsmtuners.com/threads/exhaust-the-straight-scoop-on-backpressure.168578/

http://ls1tech.com/forums/advanced-...ackpressure-vs-scavenging-one-do-we-want.html
 
Never mind guys. Apparently I can't trust two shops to do compression tests. I bought my own gauges and just did it myself. All but cylinder 3 is at 165-170. 3 is at 120.

Wasted so much time and money.
 
Jag said:
Never mind guys. Apparently I can't trust two shops to do compression tests. I bought my own gauges and just did it myself. All but cylinder 3 is at 165-170. 3 is at 120.

Wasted so much time and money.
Click to expand...

that sucks, it's hard to find good help these days.
 


Both scavenging and flow velocity are more important for sure.

They need to be addressed if your build requires it. Like a V8 motor build or something turbo charged or whatever.
 
Yeah. I'll have to go to my backup Grand Prix while I tear this one down.

I just wish I would have done my own compression test first.
 
I agree with Five, use a borescope before a teardown cause it could save you a ton of time. Also you can get a borescope from harbor freight, use it, clean it and return for refund lol.

Sent from my LG G3
 


Te one from Harbor Freight is too large to fit into the spark plug hole and the resolution is not good enough to see the edges of the piston when it's far enough down the cylinder to see the edges.

Jeff
 
brandon got that mini cam scope thing for 10 bucks on line. it fits in a plug hole, and had damn good vid quality for 10 bucks. you would see chipped pistons for sure. even scored walls with it.
 
I've been looking through messages for the last hour trying to find one like that that Matt sent me and can't find it. Yeah it was really small like a 1/4" or smaller.
 
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