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AR15.COM
5/29/2005 8:46:36 AM EDT
I have a 2000 1500 sierra
5.3 V8 with the new coil over plug setup, 1 coil for each cylinder
Lately the problems I have been having are.
Hard starting when hot
rough idle
engine light comes on when idling or when driving slow.
engine light will go off after a couple of days driving.
New EGR valve with no change in symptoms.
I have some ideas but want to get some feedback from anyone else that would have a different view of things.

Read codes, got 0300 misfire
and 0304 misfire in cyl. 4
Gonna swap the wires and coil to another cyl. and see if it changes.
5/29/2005 9:00:37 AM EDT
[#1]
Go to autozone, have them pull the codes when the light is on.... that will tell you what senor is having problems.

I would guess at Oxygen sensor causing incorrect fuel mixtures, but until you get the code, it's a stab in the dark.
5/29/2005 9:00:46 AM EDT
[#2]
Get the codes pulled.

It's the first place to start.
5/29/2005 9:02:37 AM EDT
[#3]
yeah you could always change the ignition wires, plugs...
5/29/2005 9:04:22 AM EDT
[#4]
That's the problem.
nobody around exept for dealers and I have NO TRUST in them.
5/29/2005 9:12:35 AM EDT
[#5]

Quoted:
Go to autozone, have them pull the codes when the light is on.... that will tell you what senor is having problems.

I would guess at Oxygen sensor causing incorrect fuel mixtures, but until you get the code, it's a stab in the dark.



Get a Chilton, then buy the sensor and your problem is done.

5/29/2005 6:12:48 PM EDT
[#6]
I guess based on your information without any knowledge of engine size, codes etc .
I would guess that you have a leaking fuel pressure regulator.  Pull off the small
vacuum line that feeds it and see if it leaks fuel.  The diaphrams rupture and leak
fuel into the intake.  May do it all the time or be more pronounced hot or cold.
Hope this helps.


Dustdevil out.......
5/29/2005 6:15:20 PM EDT
[#7]
I vote O2 sensor.
5/29/2005 6:18:30 PM EDT
[#8]
If you have the v6 your distributor is probably corroded. If you truck has a cap check it as it is the easiest fix and to diagnose.  We had a 2003 WT silverado and it was a POS. They had a recall on it. We have the 6.0 v8 now.
5/29/2005 6:23:19 PM EDT
[#9]
Also check for carbon buildup in the EGR valve. If the cabon breaks loose, it may cause the EGR to stick open, rough idle, poor fuel economy, and a general PITA attitude from the truck... fullclip
5/30/2005 7:37:57 AM EDT
[#10]
Some great suggestions.

The fuel regulator and egr have been GM issue's since the early 90's and have been a great source of headaches for DIY'ers and un-informed mechanics.

Even though the newer line of vortec engines have moved away from the designs that plagued them in the past, they could still be an issue.

5/30/2005 10:46:07 AM EDT
[#11]
Ok going out to check the fuel reg. now.
5/30/2005 11:21:27 AM EDT
[#12]
Buy a scan tool if there is no parts store nearby that will read them. It will pay for itself first time you stop yourself from guessing and swapping the wrong part.