1996 Chevy Tahoe Engines skip

1996 CHEVROLET TAHOE
130,000 MILES • V8 • 4WD • AUTOMATIC
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YOTERMOTOR
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It all started out with a cracked head. They diagnosed that the number two cylinder was misfirin as well as the coolant going out the exhaust..So i had the head replaced along with a complete top end gasket setas well as, plug wires, spark plugs, distributor, cap and rrotor. The truck does not run really bad but it still has a skip. Took it back down to diagnose, still saying the number 2 cyl. misfiring. So, i had a complete compression test done and here are the results......#8=125psi, #6=125psi, #4=150psi, #2=125psi, #7=125psi, #5=125psi, #3=125psi, #1=175psi. Where i had this done the diagnosed that the number 1 cyl. sensor needed to be replaced? The vehical does run aliittle rough, i guess more than a skip. One other thing is that every time i go to start it , it sounds like a crashing machine untill its warmed up alittle....this includes after sitting for 20-30 minutes. I would really apppreciate any suggestions you would have, Thanks, Riick
May 11, 2009 at 7:20 AM
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RHALL77
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what do you mean by a number 1 cyl. sensor . do you know if they check the plug wires and see if they are ok. do you know if they replace the cap and rotor also
May 11, 2009 at 7:48 AM
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YOTERMOTOR
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[quote:429904d9e5="rhall77"]what do you mean by a number 1 cyl. sensor . do you know if they check the plug wires and see if they are ok. do you know if they replace the cap and rotor also[/quote:429904d9e5]

All of the spark plug wires brand-new as well as the cap and rotor. One of the mechanics said something about the number one cylinder sensor being bad? I was baffled myself. Another thing I forgot to mention is that the check engine light comes on and goes off from time to time. Could this be an O2 sensor going bad? Everything else looks really good and there is no reason why it should run rough, the coil be another option? When I'm on the highway you wouldn't even know anything is wrong, seems to run pretty good then.............again, what about tthe knocking at start ups?
May 11, 2009 at 9:50 AM
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RHALL77
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have it scanned for trouble codes and let me know what you find. the knocking noise, does it sound like a tapping noise
May 12, 2009 at 5:36 AM
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YOTERMOTOR
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[quote:0ffcbdf6f7="rhall77"]have it scanned for trouble codes and let me know what you find. the knocking noise, does it sound like a tapping noise[/quote:0ffcbdf6f7]

Yes, a very loud tapping noise. Here are the codes

122
133
300
May 13, 2009 at 4:13 AM
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RHALL77
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check your connection at the TPS sensor and make sure it is plugged in and the plug is not damaged. it is located at the throttle body on the intake. also sounds like you have a lifter bleeding down causing the noise. with out hearing it its hard to tell. and yes it could be a o2 sensor going bad also. but that wouldnt cause a tapping noise. does the scan tool your using have a data stream to view values of the sensors
May 13, 2009 at 4:26 AM
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YOTERMOTOR
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[quote:a024264a4d="rhall77"]check your connection at the TPS sensor and make sure it is plugged in and the plug is not damaged. it is located at the throttle body on the intake. also sounds like you have a lifter bleeding down causing the noise. with out hearing it its hard to tell. and yes it could be a o2 sensor going bad also. but that wouldnt cause a tapping noise. does the scan tool your using have a data stream to view values of the sensors[/quote:a024264a4d]

I did go back and get the data. It came up with the possible causes just as you said. TPS, O2 sensor, is also said it was misfiring in different cylinders meaning a possible coil as well. Now with the lifter bleeding down, the loud tapping stops after the engine is warmed up, could this still be the case? Should I try replacing the lifters?
May 14, 2009 at 4:47 AM
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RHALL77
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another this to check is see if the valve is adjusted correctly. they may have left the rocker loose enough to cause the tapping noise your hearing
May 14, 2009 at 4:55 AM
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YOTERMOTOR
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[quote:0450996d28="rhall77"]another this to check is see if the valve is adjusted correctly. they may have left the rocker loose enough to cause the tapping noise your hearing[/quote:0450996d28]

This loud tapping noise started back in the winter. Every time I started the truck it was very loud for about three or four weeks and then it went away for well over a month, and now it's back?? Why would this stop and then come back? This was happening before the top engine was torn down. Quite strange, any idea why it would come and go?
May 17, 2009 at 6:46 AM
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RHALL77
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I almost need to hear it to tell you. its hard to figure out just in a forum. did you check to see if any of the valves are loose. it may be a lifter bleeding down causing the noise
May 18, 2009 at 7:35 AM
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