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 16, 2011 at 1:44 AM
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JACOBANDNICKOLAS
  • ✓ASE Certified Mechanic
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  • ASE Certified Mechanic
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 10:27 PM
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PBRYAND13007
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I am trying to determine what it is. I will let you know as soon as I find out.

Jan 21, 2011 at 11:01 PM
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JACOBANDNICKOLAS
  • ✓ASE Certified Mechanic
  • 110,194 POSTS
  • ASE Certified Mechanic
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 22, 2011 at 5:06 AM
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