the car is stock without bolt ons.. this code is driving me its an auto 99 trans am.. the car sputters like a put put and the ses light just blinks and it has no power. all packs are getting spark and the engine fuse isnt blowed.. any suggestions

 

Check that PVC line coming out of the passenger side of the throttle body.

I had a hole on the bottom of that rubber 45 degree elbow. others have the hard plastic line crack in the back.

 

sometimes i crank it up first start and it runs smooth for like 2-3 seconds then it starts running like crap immediatly

 

I have a '99 Sonoma that I was getting a PO300 Code as well as another code (the # escapes me at the moment) which was Crankshaft Position Sensor Intermitent Signal. I replaced the CKP Sensor with a stock GM piece and it seems to be better. Is the PO300 the only code you're getting?

 

its shooting a p0412, and p0418 secondary injection valve

 

any other suggestions

 

It sounds like your check valve. you can replace it, or swap them from side to side to see if the error changes numbers.

 

what valve is that and what does it do

 

Thanks!!! my car also has the po300 code and after I read this
I went out to check my pvc line and sure enought it had a big
hole at the bottom of the elbow.

 

happy got your problem fixed.. im still struglling with mine

 

happy got your problem fixed.. im still struggling with mine

 

so what codes are you getting?

P0300
P0412
P0418

Is that it, or are there more?

Did you check that elbow? and try swapping the A.I.R. Check Valves?

 

https://ls1tech.com/forums/general-m...mg-begins.html

I don't know if this link will work for you:
http://www.autozone.com/autozone/cat...entId=cat30067

But that shows what the check valves look like.

 

i took those off and put block offs

 

hey i am new to this form stuff and dont know how to start my own, but i have a 99 fbird with a 3.8 and im gettting the multiple random missfire aswell. i dont really have a clue of where to start, iv replaced all my coils plugs and wires. it has been sitting for over a year now due to this problem. any suggestions please

 

Hey check your crank sensor it on the passenger side above the starter. This happen to me it would run awesome for about 2 sec then have no power. Or it could be your crank sensor.
Also check your airfilter sensor that plugs into your air filer that small one in front of the T.BODY