random misfire code/hard start/skip

[skyhighsami]

I've been chasing this problem for awhile. I've replaced fuel pump, filter, plugs, coil, cap, rotor, altenator, battery, serpentine belt, idler pulley and tensioner, cleaned the throttle body, maf, and egr yet it still happens. Only code I get is random misfire and when I start it it turns over for 3-4 seconds before it starts. At idle there's a slight skip. I heaven replaced the plug wires but they look brand new. Help me out, I'm going crazy

 

[SunlitComet]

And this code is?

 

[animalfries]

Random misfire is p0300. I have the same code and same symptoms and have just begun looking. It takes a scary 4 seconds to start and idles bad. The code only comes on at idle and actually blinks sometimes idling. As soon as I rev it or put it in drive it stops blinking. On the throttle it runs great. I'll let you know if I find anything.

 

[SunlitComet]

Test your injectors.

 

[skyhighsami]

You have described my problem perfect. None of the stuff I replaced helped

 

[Ceejkay]

the biggest thing you have not replaced is your spider assembly (injectors)

 

[animalfries]

Holy F'n S you guys. My tahoe now purrs...it literally PURRS.

I spent about 8 hours and 50 minutes of my 9 hour work day yesterday looking on the internet for fixes. Some guy says pull the vacuum hose off the top of your fuel pressure regulator. If it smells like gas it's gone bad.

Well, I pull mine off and the hose dumps about a handful of gas up my sleeve. I hit up autozone and $59.99 later my baby fires in two turns, idles like a champ, and I let it run for 15 minutes with no CEL.

Apparently, the bad regulator messes with vacuum pressure and the vacuum pressure messes with the fuel/air mix and creates a miss.

I already gave my wife my credit cards in fear of mass internet orders and buying the town drinks in celebration.

 

[SunlitComet]

tbi system I assume.