1999 Tahoe 5.7l LS performance issues

[Braedyn]

Hey guys. I have a 1999 tahoe with some issues that i can't figure out. When starting and running the engine sputters and hesitates when accelerating...and it smells like its running super rich. It is throwing codes for the CPS and O2 sensor. But thats it. In the last 6 months ive replaced a water pump, knock sensor, plugs and wires, distributor cap and rotor, crankshaft postion sensor as well. And it still acting up. Not sure where else to go with it. Its a rebuilt block. The first one lost oil pressure at about 160k. This one has about that same amount of miles on it. Im not sure what else to do. I also did a seafoam fuel oil AND engine treatment on it 2 weeks ago. Nothing. Please help!!

 

[east302]

What are the code numbers?

GM has diagnostic tables for each, so resolving the codes would be a first step.


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[Braedyn]

Its got 3 codes. P1345 Ckp/cmp correlation, a p1345 with a little pd at the end, and p0140 which is the O2 sensor...outside of that...nothing. Timing is my next guess. Cause i already put a brand new CPS in it last week. And it idles fine. Between 700 and 1000 rpm. It only has issues when im accelerating.

 

[drakon543]

p1345 could also just mean your not at 0° timing. 1 tooth off and the distributor would half to be turned to clear the code. if you drop the distributor in just right the flat edge of the distributor will be parallel with the back edge of the intake. also if the gear on the bottom of the distributor is worn it can cause that code. if your timing is off it will can also cause the o2 sensor code since its not running right. pull the cap off and check for play turning the rotor. there shouldn't be much at all if there is your distributor needs to be replaced. also the only way to properly check the timing is with an advanced live data capable scan tool that has cam retard function.

 

[east302]

Has the distributor been removed or rotated (with the hold down clamp loosened)? While defective parts can come into play, that correlation code often comes after a distributor removal/replacement or if the distributor housing is rotated with the hold down clamp loosened. A scanner (or downloaded app with a Bluetooth ODB adapter) is then used to set the CMP offset to avoid having the code set.

Here are the diagnostics for P0140:

















VCM connector C1:








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