I bought a 2011 HHR Panel about 2 months ago with 170,00 miles and it ran perfectly up until 2 days ago. Felt a slight miss around 50ish, no code, next day it missed a few times a couple of miles down the road. I turned around and on the way back home the engine light came on and ran like crap. Checked codes and got p0302 #2 cylinder misfire. I swapped around the spark plug boots and still misfire on #2 cylinder, I changed plugs about a month ago ac Delco 41-103, all plugs still look good, Cleaned the MAF sensor and throttle body . Just did a compression check cylinder #1 190, #2 190, #3 190, #4 200. I'm running out of patience, anything else I should be checking/replacing? Thanks

 

Check the wires and connections to #2.
Look at the timing chain; any slack between the sprockets is bad.
Check the coolant level under the pressure cap, for possible head gasket leak.
Check the ECM connectors. Pins get bent or push out the back.
If tried to gap the plugs you may have damaged the whisker. I have a set in my garage as a reminder.
By "boots" I assume you mean the coils.

 

Didn't gap the plugs, all the connections you mentioned have been checked and good. I have not checked the timing chain yet, I guess it's next on the list. Very frustrating when it ran perfectly until 2 days ago.
The coolant is at the proper levels and oil is clean.

 

Did you check fuel injectors and fuel pump pressure?

 

Replaced #2 injector, going to go ahead and replace all of em, haven't checked fuel pressure, I'll check that before I pull the valve cover and check the timing chain one day this week. I guess I'll have to ride my trusty 74 Shovelhead 😜

 

Clean out the fuel rail , replace the orings and ceramic cups with the injectors

 

Want to trade the bike for a working car?

 

No way in hell...😜

 

I may need to upgrade the car a little. Nice.

 

Ok I just checked the fuel pressure, 52 engine off , 58 engine running, drops down to 52 within a few seconds after turning off. Don't if that's good or bad ?