At a loss

Charcarius · 05-08-2008, 06:49 PM

Ok guys I have an 2002 1500 silverado with the 5.3 in it. I got about 135000 miles on it. I am not a mechanic by any means, merely a carpenter. My check engine light came on, got the code checked it read ramdom cylinder misfire/malfunction. I changed the spark plugs. Its still doing the same thing. I can tell it is losing power, and I have what sounds like a high pressure spray when I hit the gas any more than an old grandma in a lincoln. Can it be the coil packs or the injectors or... what I desperately need some guidance. I can;t really afford to take it to the shop and the book doesn;t have this in the troubleshoot that I can find.

junior3382 · 05-09-2008, 01:30 AM

Having a multi cylinder misfire can have several causes. Spark plugs being warn, plug wires having a dead spot, coils grounded out, rotor inside dist is off time by a slight. That in the ignition system. Problem could also be with injectors or mass airflow... is the only warning light a po300 code? it is not signaling running lean or too rich is it?

Being that is has 135k on it, and it is losing power, I would guess it needs a full tune up. Manufacterer recomends complete replacement of plugs and wires every 60k and coils and dist every 120k.... I would start there. being a carpenter and not a mechanic, wires may be easy, but I would also recomend bringing it to a shop for the dist. Timming has to be perfect, and they have the proper knowledge and tools. Good luck bud, I hope this helps.

Charcarius · 05-09-2008, 04:31 AM

Thanks man, helps a lot. The plugs and wires were pretty easy. I was going to go with the coil packs next I guess, but I think I will take your advice on that thanks again.

Sneakysportsman · 05-09-2008, 05:37 AM

Having a high pressure spray sound means you have a vaccum leak some where. Also having a code that says random cyl misfire means that it isn't only one continious cyl not firing but it is throught the engine. You have a lean engine miss. Caused from a vaccum leak.

Charcarius · 05-09-2008, 04:54 PM

I take it that would also explain the whistling sound I get occasionally when the engine is cold in the morning and I am pulling out. I thought it was a belt at first but I know enough to know that it isn;t a belt.

How would I check for a vacuum leak?

Also since it has so many miles on it how hard is it to change all 8 of thouse coil packs. It looks easy but i know how things like that start out
Thanks for all the help guys

Sneakysportsman · 05-09-2008, 06:45 PM

Mega bucks!!!!! It isn't hard but you have a vaccum leak, Get a piece of tubing or a stethascope an dhold to your ear and move all around the engine and this process will pinpoint a vaccum leak.

05-08-2008, 06:49 PM	#1
Charcarius Junior Member Join Date: May 2008 Posts: 4	At a loss Ok guys I have an 2002 1500 silverado with the 5.3 in it. I got about 135000 miles on it. I am not a mechanic by any means, merely a carpenter. My check engine light came on, got the code checked it read ramdom cylinder misfire/malfunction. I changed the spark plugs. Its still doing the same thing. I can tell it is losing power, and I have what sounds like a high pressure spray when I hit the gas any more than an old grandma in a lincoln. Can it be the coil packs or the injectors or... what I desperately need some guidance. I can;t really afford to take it to the shop and the book doesn;t have this in the troubleshoot that I can find.

05-09-2008, 01:30 AM	#2
junior3382 Senior Member Join Date: Mar 2007 Location: Currently, I live in Lancaster county, Pennsylvania. Posts: 3,170	Having a multi cylinder misfire can have several causes. Spark plugs being warn, plug wires having a dead spot, coils grounded out, rotor inside dist is off time by a slight. That in the ignition system. Problem could also be with injectors or mass airflow... is the only warning light a po300 code? it is not signaling running lean or too rich is it? Being that is has 135k on it, and it is losing power, I would guess it needs a full tune up. Manufacterer recomends complete replacement of plugs and wires every 60k and coils and dist every 120k.... I would start there. being a carpenter and not a mechanic, wires may be easy, but I would also recomend bringing it to a shop for the dist. Timming has to be perfect, and they have the proper knowledge and tools. Good luck bud, I hope this helps. __________________ *The Blazer is dead, so I pumped her with lead, laid her to bed, and bought a FORD instead!*

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05-09-2008, 04:31 AM	#3
Charcarius Junior Member Join Date: May 2008 Posts: 4	Thanks man, helps a lot. The plugs and wires were pretty easy. I was going to go with the coil packs next I guess, but I think I will take your advice on that thanks again.

05-09-2008, 05:37 AM	#4
Sneakysportsman Senior Member Join Date: Jun 2007 Posts: 296	Having a high pressure spray sound means you have a vaccum leak some where. Also having a code that says random cyl misfire means that it isn't only one continious cyl not firing but it is throught the engine. You have a lean engine miss. Caused from a vaccum leak.

05-09-2008, 04:54 PM	#5
Charcarius Junior Member Join Date: May 2008 Posts: 4	I take it that would also explain the whistling sound I get occasionally when the engine is cold in the morning and I am pulling out. I thought it was a belt at first but I know enough to know that it isn;t a belt. How would I check for a vacuum leak? Also since it has so many miles on it how hard is it to change all 8 of thouse coil packs. It looks easy but i know how things like that start out Thanks for all the help guys

05-09-2008, 06:45 PM	#6
Sneakysportsman Senior Member Join Date: Jun 2007 Posts: 296	Mega bucks!!!!! It isn't hard but you have a vaccum leak, Get a piece of tubing or a stethascope an dhold to your ear and move all around the engine and this process will pinpoint a vaccum leak.