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L67 Misfire, who knows vacuum lines? New info on the misfire.


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Posted

Check out my last post for the new information on my misfire.

 

So I got new o-rings on my injectors, my compression is good, my ignition is good, and my cylinder two misfire went away, but now it turned into a multiple cylinder misfire or P0300. All cylinders are firing but I got some major vacuum issues I need to resolve but I have no other car to compare too. To let you know how bad it is, I have no vacuum going to my MAP sensor, when I bought the car there were no lines going to it.

 

Ever since it went from the cylinder 2 misfire to the multiple misfire, it went from running like a raped ape to running like dog shit. I'm pretty damn sure it is my vacuum lines, otherwise how would I got about testing O2 sensors. Plus my cat is rusted out, normally I would straight pipe it (no emissions here :biggrin:) but how would that effect the downstream O2 sensor?

Posted

Sadly, its not those. Just removed them and it is still running like crap.

Posted

Plugs and wires are new, and before I replaced the valve covers I just had that misfire in cylinder 2. I guess I'll pull the coils off quick.

Posted

Alright I just rescanned the car and I also get the code P1200, and it tells me it is the fuel air metering system? This sure would make a lot of sense to cause a multiple cylinder misfire.

Posted

a vacuum leak in a car that uses a MAF for fueling can cause random misfires due to unmetered air getting into the cylinders, causing a lean condition and therefore, misfires.

 

in a MAP only car, it doesn't cause misfires, just idle issues.

Posted

a vacuum leak in a car that uses a MAF for fueling can cause random misfires due to unmetered air getting into the cylinders, causing a lean condition and therefore, misfires.

 

in a MAP only car, it doesn't cause misfires, just idle issues.

 

Yes I got a MAF, and yes my vacuum lines are completely FUBAR. I need some good pictures. Like I said, I got no lines going to my MAP sensor and if the diagrams I have looked at are correct the ones that are in place are wrong.

Posted

Also my misses were kind of erradict, sometimes they were there, sometimes they were not, and now everything has just gone to hell. I drove the car down the driveway and had it idle perfectly fine for about 15 minutes before hand, but the moment I went down the street and put it under load it started missing and hasn't stopped since. Could this be my ICM? Tomorrow I'm going to check my grounds and make sure they are all good, but this damn motor makes me want to RRRAAAGGGEEE!

Posted

Ok so I guess I should name this car Christine, I went out today and there was no misfire whatsoever, then after about a minute of running it began misfiring, then it went to no misfire. I then took it out for a drive and at some points it was limping and at others it was full of power (obviously it was going from no misfire to a very bad misfire in pretty much every cylinder.) Any ideas?

Posted

tap(smack) the MAF while it's idling, see if that causes any change...

Posted

Check out my last post for the new information on my misfire.

 

So.... why make a new thread???

 

Merging....

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