2000 zr2. new stuff. Headers, coil wires, plugs, skip white distributor. relearn done, timing set. ac delco cap rotor, plugs.

Now the gremlin Start up runs idles great, when it gets up to full temp I have a random skip/miss. solus pro shows no misfires. took off throttle body and looked for washed down intake, nice and black, all good there. did a leak down, 60 psi and held steady for 20 minutes.

Next try. what I`m thinking is since it doesnt do it till fully warm maybe its a lazy o2 sensor. Any thoughts any one?

 

Could be a lazy O2, but you would see that in the data stream. On your Solus Pro, graph both upstream O2's and watch how they perform. Sweeps should be nearly identical.


You mentioned that you had a relearn done. That procedure is for the crankshaft position sensor, and the data needs to be correct. Installing a distributor on the other hand, requires camshaft retard to be checked and adjusted if necessary. This is an adjustment, not a relearn. If camshaft retard is out of spec, there will be crossfire going on inside the distributor cap, guaranteed. Depending on how severe the misfire is, it might not set a DTC.


The PCM uses combined data from the crankshaft position sensor AND the camshaft position sensor to detect, and accurately identify, cylinder misfire. If the crankshaft position sensor relearn data, or camshaft retard adjustment are incorrect, cylinder misfire data could be nonexistent or incorrect.

 

Both crankshaft data and cam retard are correct. already got the o2 sensors. will change when rain stops. probably original anyway and may help mileage. I keep going back to why when its fully warm and not when cold

 

Could very well be lazy O2's. The PCM ignores them in open loop operation.

 

We will see, I`ll post results

 

AC Delco or Denso, stay away from Bosch, (response time is too slow).

 

ordered from rockauto, was supposed to get them today, they didt show. sighh https://www.rockauto.com/en/moreinfo...=1361461&jsn=1

 

Good job! Those will work just fine.

 

Bingo, cured the issue.

 

Yee Haa!