Well the cobalt addiction DP was clogged,when my buddy put it on the reader it said "bad catattalitic converter and random cylinder misfire.I just swaped back on the stock Downpipe and have made an appointment with the dealer for wedsnesday. Can a clogged cat cause a random cylinder misfire due to a build up of backpressure due to carbon buildup?

 

could be a possibility....

 

now that I got the stock DP on now,Im gonna give it a good run on the highway to try to get some of the carbs out,cause damn i have no acceleration right now

 

Yes mike it can cause random cylinder misfire

If its clogged enough it will stall/kill the engine especially under heavily load or high throttle usage.

 

my car throws the same code for the random misfires, and another code with barametric pressure. Not really sure.

 

The missfire will make lots of excess hydrocarbons which will plug the cat. Its not the cat causing the missfire, but the missfire killing the cat.

First you have to fix the problem of the missfire then get a new cat.

 

so what causes a random cylinder misfire???

 

Plugs, bad timing....

 

well maybe I'll change my plugs then,being lazy

 

Always a fast and cheap way to eliminate possibilities. Got the good gas in there I am assuming.

 

94 only and always cheveron

 

The dash hawk reads all the things that your throwing codes for. I was wondering what all the things where needed for an this just answered a few questions i had

 

my 07 has been to the dealer three times for a cylinder misfire in cylinders 1 and 4 and now finally they decided to fix it. gm told them that to test the injectors then clean them then test them again. so now they decided they are bad and going to put 4 new injectors in. my car has 2600 miles on it not even a month old and has been to the dealer 4 times and in the shop 13 days. they had to replace the stock clutch at 586 miles. i hope it gets better. lol

 

just swapped the plugs for autolites extremeperformance and the off idle seems to be gone,my second from the left stock plug had build up the other three were fine

 

Whoever said a clogged cat can't cause random cylinder misfire is wrong. It can and will if its clogged. Its like trying to blow through a clogged straw, a little air gets through "Random" spots but its still clogged.

Random Cylinder Misfire can also be caused by:
Bad Timing
Fouled Plugs
Clogged Injectors
Faulty Wiring

and in older cars bad ignition cassettes when the plugs shared a cassette.

 

nice writeup.thanks

 

Catalytic Convertors don't clog on there own for no reason... Cats dont die, they are murdered...

The Missfire clogged his cat and now he has to fix the missfire. Hopefully it was the plugs, but more than likely its the timing from those shiny new cams he has... I'm sure they crank the timing way up and hes getting a little pre-ignition now and again. I would be less into the dealer and more into the guy who did that cams.

 

good point about the cams,but I have run it two months with the cams and did not have this problem,Im betting that I'm runnin so rich I fouled the injectors cars runnin like **** again,i step on the gas and it bogs out

 

How do you know you are running rich if you don't have a wideband? I keep telling you once you start modifying having one is essential.

 

I knew this from going to that shitty dyno

 

Haha its also easy to tell if theres black smoke or you smell gas..... Haha Too rich if you can smell it with a cat.