08 idles and runs bad

[JJB]

So Im slowing down for a stop light and all of a sudden the car starts shaking, and when we stop its sounds like its missing pretty bad. Ran the codes and it came up with the p0300 random misfire. It lists so many potential causes im looking for help. A couple months ago i had to replace an ignition coil and the icm.

 

[Fivefingerdeathpunch]

I'd start with replacing all spark plugs with new AC delco's, then cleaning the MAF sensor and Throttle body.

 

[JJB]

There is no throttle body its injected, sorry.

 

[Scottydoggs]

you most certainly do have a TB, and they get dirty and make the car run poorly. its at the end on the tube from the air box where the air filter is.

it has a butterfly flap like a carb, behind it is where its dirty.

 

[JJB]

Ok, but would these problems cause it to start missing just that quick?

 

[Scottydoggs]

the misfire is most likely your plugs are shot, and the wires, you have the icm and coils replaced already.

a dirty TB will just make it run rough and a rough idle and stalling, hard starts.

when i bought my car i had a po300, plugs and wires fixed that.

 

[JJB]

Ok, ill try the cleaning and plugs and wires, thank you and ill post again asap.

 

[Scottydoggs]

dont clean them, replace them, you can get copper plugs for 2 bucks each, wires for 30, good old stock replacement is all you need.

 

[JJB]

That's what i meant, replace the plugs and wires and clean the maf and throttle body.

 

[sLpGPGT]

does the car shake when it ALMOST comes to a complete stop every time u stop or just sometimes?

 

[JJB]

Its just missing bad, it gets worse as the car warms up. I forgot to mention that i have put injector cleaner in it already.

 

[JJB]

Its missing bad, its rough at idle but havnt taken it at highway speeds, it still runs pretty rough around town. it seems to get worse as it warms up.

 

[JJB]

Hello again, I was testing the ignition control module. Is every male spade terminal (6) on the module supposed to be getting 12v when the key is turned on? Or is just one of them supposed to be getting 12v per ignition coil?

 

[bmx6454]

yes. and ive seen misfires on many different cars. and it is almost always plugs/wires. sometimes it can be fuel injector. but i highly doubt that on an 08.

 

[JJB]

Got the car fixed today. It ended up being the ignition control module. I replaced it and a coil just 3 months ago. I wouldn't have expected it to be a new part i just replaced. Thanks for the help to all of you. Until next time...lol.