First time ever asking for auto-help online.
I started getting misfires on my car last week. Check-engine light was flashing and engine was rumbling. Took it to Auto-zone to pull the codes and it said it was a misfire on cylinder 2.
Took it to a shop, they replaced the ignition coil on cylinder 2, left it at that. Engine misfired the next day, auto-zone gave me the same report again.
A friend and I changed out all the spark plugs (it was a nightmare to get the ones in back) drove it home fine. Two days later (no driving on the day between) it misfired again.
Looking at it, I realized there is a missing piece of vacuum hose going from the T joint just off the vacuum switch valve to the vacuum tank. So my question, is this the culprit? If not, what on earth is going on with my vehicle?
No I haven't pulled the check engine light report again. That's on today's todo list after work along with replacing the vacuum hose bit.

 

Welcome to Club Lexus and your first post!

 

#1 - we know nothing about what car you have, how many miles, has there been any work done, how long this problem has plagued you, etc
#2 - why not start with the cheap and easy? Replace the hose. For that matter due to likely age and miles (not provided) changing all the vacuum hoses will probably cost you <$20, take only a few minutes, and is considered a maintain item due then report back. Replace each hose, one by one so as not to get them confused and put onto the wrong fittings. There are many maintenance items that should be replaced on 20 year old cars do a search they've been talked about many times over definitely vacuum lines is one of them and yes vacuum lines will throw codes, cause your engine to idle very high, give terrible misfires and low power, poor gas mileage... it should be a very immediately obvious performance improvement the car should run much smoother

Now go back and check to see what mfg the new coil is, if it is aftermarket versus the OEM Denso you're lkely not going to be happy

 

STOP Throwing money at it IF U have a blinking check engine light in ANY car that means the engine has suffered catastrophic damage meaning u need a new motor.

 

agreed, the idea of ever applying solutions without understanding what problems are boggles my mind, be that business, life, or cars. Dealerships and mechanics prey upon the uneducated. The tube cost about $1 at Autozone or any autoparts store, would take even a novice less then 3 minutes to replace and will likely solve the problem, instead the OP opted for rear plugs which likely cost >$800 to replace with no resolution... dealer or indi is thrilled but customer not so much.

Replace ALL the vacuum lines, one by one so you know they are going into the right place. Measure, cut, install, report back. In this case relace that single vacuum then try it out it shold run much much better... once it does replace them all. This will take maybe an hour to do all of them and cost maybe $40 (careful as I think there are two diffrent sizes). If it were me I would return to the mechanic and demand a full refund as well as an apology since their trusted diagnosis did not resolce the problem in any way.. they were trusted to fix it and they did not customer should never be held liable for their mistake. Saying this NOT to beat up the OP but rather as a hopeful reminder/example of how going about repairs with the wrong mindset is not only VERY costly but takes much more time and can yield you no results other than frustrations and unnecessary expense and time. I've seen it often on every forum sometimes costing posters their entire car or tens of thousands for following sillly advice even from mechanics whom they think they trust.

CEL light is not good, blinking CEL is really bad!