Knockabout

2000 jeep grand cherokee 4.7
I haven't determined where its coming from. When i try to hear where its coming from its under the hood driver side closest to the firewall. I have pulled all the injector one by one with no noise difference. FACT its due to running with no oil. she isn't throwing codes other the my normal evap and 02. how to can i determine where its coming from or what else i need to check?

Veeb0rg

if its knocking, let it in!

Cherryokee

Y'know, that purge valve or relay thingy? It is located where you described and sometimes makes a lot of noise...and it sort-of sounds like it might be an injector....tick.tick.tick.tick.tick. I know, I know, you said "knocking" - but one man's "knock" is another mans "annoying tapping sound" - and you also said something about Evap codes too. I first suffered this failure with my 99 XJ 4.0 and had the same code combo on that. Clear your codes and run around again. O2 and Evap codes can be a "chicken or the egg" scenario. Check for code priority (because I forget which code set first). If the Evap code returns relatively quickly then clear codes again and start your diagnoses at a possible defective vented gas cap. If that doesn't help then do purge-system smoke-testing. The Evap system canister, etc, is hidden under the fender, behind the drivers side rear wheel.