Man i just had the same problem a cpl days ago and come to find out it was a loose plug wire on the #3 plug. Changed to TR6's for the oncoming nitrous replaced wires (MAKE SURE YOU HEAR THEM SNAP ON...!)and everything is fine now. Oh and if your truck is tuned, i wouldnt suggest running any cheap gas prolly some good 93 or whatever is available.

 

ok well I had my friend scan the truck this time with his snap on scanner and he got the same code PO 300(random misfire) and PO440(evap leak, emission failure??)...now with his scanner we could watch when the truck skipped and each cylinder it was...and it was all of em just at random(guess that code was right)...I really think its the plugs and maybe the wires...I have taken off each wire and like you guys have said "hear them snap" and still the same scenario...

as for the gas its 93 and I filled up about a week ago...but I will say that my mileage really has gone down the tubes...the truck only does it bad bad once and a while...today it did it along on Sunday night...it just stalls then runs with my burping the throttle then stalls...and then sometimes just really rough idle...so seeing that sometime it just changes I think that it might just be the plugs(I hope)so Im going to change them tomorrow...which brings me to my next question...what plug does everyone recommend???


well I hope to report back with good news...thanks again to everyone who has left feedback!!!

Also could the other code have anything to do with it???

 

Tried doing any SeaFoam yet?

 

If it's just a cold problem,just concentrate in that area. Did you clean the IAC in the throttle body?

A guy hear at work has a 2000 5.3 and had to clean the IAC to cure a cold start problem(do a search on it). He also replaced his fp regulator a few months ago. It's on the left(driver's side)fuel rail...pull the vac line to the regulator...any presence of gas means it's bad. The part was only about 50 dollars.

 

I just did a complete sea foam job and about 2 years ago I did replace the fuel press. reg.(not to say she **** the bed) so it is something I will check...

the cold start problem is hard to answer...I mean 'cold start' means that 1st time starting for the day correct...or you could say that the ambient air temp is really cold...which air temp doesnt affect it so much...its been around 40-50* so I dont think thats it...but maybe the fact that it was the first of the day???...I dont know anymore...lol...

Thanks again for the help!!

 

I'm definetely after the intake gaskets....have your friend watch the fuel trims with the scanner while you spray carb cleaner at the base of the manifold. Trims should start to go WAY negative, and truck will run even crappier, if not die. Give that a whirl. Cheap and easy to do yourself. And a DAMN COMMON problem aroud here with trucks.

 

If you need any more help feel free to pm me.

 

ok guys I have an update on the ol girl...well after everyones helpful advice I tried taking the vaccum line off the fuel press. reg. and there was no fuel there so I assume that its fine...tomorrow my buddy is going to bring in a fuel pressure gauge and we are gonna check it just in case...

the next thing I did was clean the IAC...let me tell you that thing was carboned up like crazy...I never knew about it before so it never got cleaned...prolly the first time is was ever cleaned and I got 154k on her...I mean there must have been an 1/8" of carbon in certian spots...so I cleaned it as well as the throttle body and MAF sensor and reinstalled everything...fired her up and ran great and the weirdest thing was my SES light went off!!...I was like thats kinda odd but Im not gonna complain...so far its much better but tomorrow morning will be the test...

I also took out a plug and they seem to be ok but I dont think they are working well with the truck so Im goin to change them...any recommondations on what you guys have had the best luck with...well lemme know and thanks for the help!!!

 

sweet i use use delco iridiums 41-985 and some people use ngk tr5 or tr6 depending on if you spray or not

 

well I also just changed the plugs with delcos and I cant believe how much of a difference it made...after I installed them I took it for a ride and throttle response was unreal...well I will let you all know how she starts tomorrow morning!!!