2000 yukon denali idle issues

[SunlitComet]

The misfires the scanner found are very recent or no? Was not clear when it was done.

 

[socalyukon]

OK just changed the TPS sensor for the hell of it and made no difference. When the truck is started in the morning on a cold start it runs perfectly smooth, but when it warms up it develops the slight shaking at idle. And the scanner would show a miss on cylinders 2,7,8.

---------- Post added at 02:12 PM ---------- Previous post was at 12:21 PM ----------

The misfires the scanner found are very recent or no? Was not clear when it was done.

yes we put a scanner about a week and a half ago.

 

[SunlitComet]

Then you need to inspect and read those plugs to learn more. Since those specific cylinders were a bit lower then others in psi and they are showing misfires perhaps run thru a valve adjustment on the whole engine. It might help a bit.

---------- Post added at 02:23 PM ---------- Previous post was at 02:21 PM ----------

Feeling like it is more an ignition part issue tho. maybe even a defective cap. Delphi, Delco or Msd are very good tho. Would not use anything else.

 

[socalyukon]

Then you need to inspect and read those plugs to learn more. Since those specific cylinders were a bit lower then others in psi and they are showing misfires perhaps run thru a valve adjustment on the whole engine. It might help a bit.

---------- Post added at 02:23 PM ---------- Previous post was at 02:21 PM ----------

Feeling like it is more an ignition part issue tho. maybe even a defective cap. Delphi, Delco or Msd are very good tho. Would not use anything else.

Yes the cap is Delphi, and Im planning to take the yukon to vegas this weekend, hopefully it holds up to vegas and back from LA. The 3 cylinders where 168psi while the rest where at 180pis.

---------- Post added at 05:55 PM ---------- Previous post was at 05:55 PM ----------

In the morning the engine runs smooth, its when it gets hot when you can feel a little misfire.

 

[socalyukon]

???????

 

[SunlitComet]

Sorry must have closed page while responding.

Then something is being effected thermally or the mixture is off some how.

 

[socalyukon]

Sorry must have closed page while responding.

Then something is being effected thermally or the mixture is off some how.

would bad o2 sensor cuase that? what you suggest I look into next?

 

[rockenthebowtie]

Let me ask you this are you sure you got the fuel injector nozzles in the correct holes when you installed the CPI injector assy ? As far as compression goes as long as your with in 25% of all compression readings it shouldn't be a problem also a mechanical problem isn't intermittent its either there or its not. Another thing that you might want to try is a top engine cleaning you might have excessive carbon build up on the intake valves allowing for improper seating of the valves causing a slight compression leakage

 

[socalyukon]

When the weather is cold outside the engine seems to run smoother. And when the engine is cold in the mornings it runs smoother, as soon as it warms up it causes issues.

 

[2000tahoeZ71]

Just saw where you changed it already. Nvm.