Am I getting ready to blow a rod?

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Forum,

 

Well I solved them O2 and MAP sensor mystery problems, but now when I keep a constant speed over 25 mph I hear a 'what sounds like' rod going or spark knock noise. If I give it some gas, or let off the gas it goes away. Is there any why you can tell for sure if you have a rod going?

 

If I do, is there anything I can do to prolong the rod from going?

 

Any help is great as usual....................

 

James

 

1991 Chevy 1500 4.3L(Z) motor