navarrodragon25
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- Nov 3, 2012
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I got a catalytic converter issue on my 1996 sierra 7.4 vortec with almost 300,000 miles.
It has new lifters,rods,cam,sprockets,chain,oil pump,stater,crank chaft sensor,cam shaft sensor,disributor cap,plugs and wires etc.
Not sure if it was caused by engine problem related to this code but I was told that if I don't fix this code issue then a new converter could be ruined.
At any rate, even though the engine rides perfectly smooth most of the time (after some major engine work) it will get Hot under the hood (even though the thermostat gauge shows a good temp) after about 20minutes and it will hesitate and surge. All clues point to a bad converter clogging up causing back pressure and eventually causing it to totally bog down and die. Interestingly it does not do it as soon as I start it and is not continuous but only starts to have a problem after the 20 or 30 minutes.
I have heard clanking and rattling under the truck twice. Once seeminlgy by the converters(there are two and fairly close together) and once more close to the rear of the muffler.
QUESTION #1 If this were a "TIMING ISSUE" woudn't it ride rough ALL the time and not so smoothly when I first start it?
... and oddly today I happened to take OFF the spark plug wire to cylinder ONE while it was running and the engine continued to run fine and was totally unaffected.
QUESTION #2 What would cause the engine to run smooth with a spark plug wire off? ( I had a loose spark wire years ago and it idled horribly from the moment I started it up)
Question # 3 Would the spark plug situation be caused by or related to the P1345 Code? ..HOW?
When I finally fix the code problem THEN I will change the catalytic converter.
It has new lifters,rods,cam,sprockets,chain,oil pump,stater,crank chaft sensor,cam shaft sensor,disributor cap,plugs and wires etc.
Not sure if it was caused by engine problem related to this code but I was told that if I don't fix this code issue then a new converter could be ruined.
At any rate, even though the engine rides perfectly smooth most of the time (after some major engine work) it will get Hot under the hood (even though the thermostat gauge shows a good temp) after about 20minutes and it will hesitate and surge. All clues point to a bad converter clogging up causing back pressure and eventually causing it to totally bog down and die. Interestingly it does not do it as soon as I start it and is not continuous but only starts to have a problem after the 20 or 30 minutes.
I have heard clanking and rattling under the truck twice. Once seeminlgy by the converters(there are two and fairly close together) and once more close to the rear of the muffler.
QUESTION #1 If this were a "TIMING ISSUE" woudn't it ride rough ALL the time and not so smoothly when I first start it?
... and oddly today I happened to take OFF the spark plug wire to cylinder ONE while it was running and the engine continued to run fine and was totally unaffected.
QUESTION #2 What would cause the engine to run smooth with a spark plug wire off? ( I had a loose spark wire years ago and it idled horribly from the moment I started it up)
Question # 3 Would the spark plug situation be caused by or related to the P1345 Code? ..HOW?
When I finally fix the code problem THEN I will change the catalytic converter.