engine repair on 98 GMC 1500 pickup

1998 GMC TRUCK
V8 • AUTOMATIC
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PBRYAND13007
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  • 6 POSTS
code PO300 mutiple misfire. I have replaced the timing belt,head gaskets,spark plugs,valve cover gaskets,intake gasket, all O2 sensors, cat, distibutor, cap and rotor, spark plug wires, and did the compression test and found that cylinders 2 and 5 have no compression and the rest of the cylinders are all under 120. What kind of prices will this kind of repair run? Should i repair the engine or replace it?
Jan 15, 2011 at 5:44 PM
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JACOBANDNICKOLAS
  • ✓Experienced Mechanic
  • 110,240 POSTS
Either you have the timing belt on wrong or you have bent or burnt valves. If the heads need redone, expect around 400.00.
Jan 21, 2011 at 2:27 PM
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PBRYAND13007
  • MEMBER
  • 6 POSTS
I am trying to determine what it is. I will let you know as soon as I find out.

Jan 21, 2011 at 3:01 PM
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JACOBANDNICKOLAS
  • ✓Experienced Mechanic
  • 110,240 POSTS
Double check the timing belt. If it is correct and you have no compression, it has to be a bent or stuck valve. The more I think about it, even a with a burnt valve, you would have some compression. I bet your timing is slightly off.

Let me know.
Jan 21, 2011 at 9:06 PM
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