Oh yea I also replaced the crank sensor and all vacuum lines including The evap system hoses

 

One other Note The Ignition control Module is the original one from 1995 if it was indeed getting tired could it cause the mis fire at idle the truck runs fantastic as long as your not sitting at a light please read back a few posts for my summary.

Thanks

 

Would that be done via a techII scanner at a dealer?

Im trying to track down a shake at idle, which feels like a misfire (same feeling if I pull a spark plug wire, just much less noticable). Im thinking that with something better than a scangauge, I might get some useful info.

 

Hey guys,
President Obama was nice enough to warranty my Injector spider today, But the new unit did not solve my Po301 problem misfire cylinder #1 symptom is (Rough Idle) Here is a list of all the stuff I have done to try and resolve this issue. If there is something You think I might have missed please let me know.
Components changed
High Voltage ignition switch (distributor) includes new cap & rotor
Coil, Plugs, Wires.
Throttle Position sensor, Idle Air Control sensor, O2 sensors, Egr Valve with screened gasket, Coolant Temp sensor. Checked Voltage at each connector as well all are at recommended voltages
within the last 2 months have replaced the Muffler and Cat Converter
New Muffler, Cat Converter
conducted a compression check on cylinder #1 compared to cylinder #5 both the same
while truck was running i applied pressure in each direction to see if a valve guide was worn but no results,

Components I have not changed
MAP sensor
Ignition control Module. From what I understand this either works or doesn't work found some post one other sites where it could possible cause my symptom
I'm kind of ready to throw in the towel Only thing I haven't done yet is a cylinder leak down test. If you have any suggestions please give them to me
Thanks

 

What were the compression readings for the rest of the cylinders? What was the psi on 1 & 5? Any signs of oil fouling on the plugs? If you squirt oil into the cylinder through the spark plug hole and re-run the compression check, what is your new reading for each cylinder?

Have you removed the valve cover and checked valve lift? It is possible that the cam lobe has wiped or one of the lifters is not functioning properly, causing a valve to not open fully.

 

No oil on the plugs, If I remember correctly Cylinders #1 and #5 held at just over 120lbs I will try putting oil down the cylinder as you suggested and trying a compression test again.
I did have the Valve cover off all appeared to be functioning correctly No broken valve spring and I applied pressure while it was running to see if maybe a valve guide was bad but didn't seem to change the skip, Was wondering if the ICM could possibly be the Problem It is the original one from 1995 I know they usually cause the truck to just stall out when they get heated up but was reading on a corvette forum of one acting up in a similar way and The crank position sensor takes it's reading from cylinder one so maybe 1 of the 2 or both are tired???

 

A fuel related problem would affect all cylinders equally with the fuel arrangement in the CPI motors.

Spark is one thought, but you have replaced pretty much everything there.

After doing the compression check, check the actual travel of the valves and compare with nearby cylinders. You will need a magnetic or bolt on base and a dial indicator to do this.

 

Is there any kind of a vacuum port on the #1 runner? Try spraying a bit of carb cleaner at the intake manifold where the #1 runner goes to the head while idling and see if it runs differently? Maybe a tiny vacuum leak that's only noticeable at the lower flows of idle?

 

Hmmm gonna have to tap my fathers brain to do that one, it's beyond my tech expertise

 

Ok I'm starting to think that I may have a VCM problem, SES light came on today so I pull out the Tech 2 scanner and DTC PO134 Heated oxygen sensor No activity detected B1 Ssensor 1 so I pull out the meeter and disconect the O2 sensor Reference Voltage is supposed to be .45volts and as low as .32 volts depending on the meter used Mine is .26-.28
on both sensors so check connectors wiggle them around with no change,clear the DTC to see if it will happen again. I take the truck for a ride and the service light SES light is back on again check DTC with scanner and have 3 more stored PO340 camshaft position sensor
circuit malfunction, PO441 Evap system incorrect purge flow, and P1406 EGR pintle position error My EGR is 1 week old with it throwing all these codes and a lower than allowed reference voltage on my O2 sensors I think my truck needs a new brain because although i still have a rough idle the truck runs like New
Any thoughts??