Q: Rough idle and code 1105 shows up. Egr valve is blocked but it has run well. on 1999 Infiniti I30

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The egr valve has been blocked for 2 years and it has been running fine until lately. I can reset codes but 1105 and misfire on cylinder 4 keep coming up.
(3) Answers
(4) Comments
Repair code PO304 first and if that helps. Find out why 4 has a misfire! Possible spark plug, coil on plug, injector, vacuum leak or low compression. Best guess is C.O.P.
When I reset the code and erase it the car runs fine and then when I restart later it the code must reoccur and it runs rough again.
rec. fuel system clean.ethanol treatment to 1 tank premium. ethanol blend in fuel causes build up in fuel system, combustion chambers,exhaust system and causes increased wear to spark plugs. build up can foul valves, injectors and trip sensors.
review when last tuned. it may be due.
I will try this I have put injector cleaner in about a month ago and it didn't seem to make a difference, can the intake have sensor hooked to the egr that is malfuncting?