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Cylinder Misfire

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cylindar misfires
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Discussion starter · #22 ·
I read it, and I also printed it out, and the comments left by someone here and when I left my car tonight I put it all in there with it. I also spoke with my friend that is an ASE certified master mechanic and currently works as a tech for a different car dealership who said this makes perfect sense and it’s the first thing that has since my car has issues at completely random times. Unfortunately he also said it might be hard to prove, especially considering the cold factor. We’ll see what the dealership says…
 
#23 ·
I think it’s more prone to missing when there’s extra fuel or some other parameter with the engine controls while it’s cold. At least that’s my take. Maybe the exhaust cam timing goes into an area that doesn’t occur when warmed up(?)

Hope you can get get something figured out.
 
Discussion starter · #25 ·
I can’t say the dealership didn’t work hard to figure it out. The tech had my permission to keep it and drive it to try and figure it out. He had his scanner with him for live data too. The problem is… the car acts up and misfires, falls all over itself, the check engine light finally comes on, and the car magically seems to correct itself. Except upon start. At an idle or low speeds the car lurches and runs very rough. The RPMS wildly fluctuate, and the car has a noticeable ticking sound. That never really goes away, although it does get better and worse at random times.
 
#26 ·
Just a guess, but it could be the crankshaft position sensor. When those start going bad, all kinds of strange timing related problems occur since the sensor is the "master" reference for where the crankshaft is in rotation. When they start going bad, the signal from them can fade in and out. Usually the signal fades out when they get hot.
 
Discussion starter · #27 ·
FKHeath said:
Just a guess, but it could be the crankshaft position sensor. When those start going bad, all kinds of strange timing related problems occur since the sensor is the "master" reference for where the crankshaft is in rotation. When they start going bad, the signal from them can fade in and out. Usually the signal fades out when they get hot.
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Interesting. I haven’t heard this theory yet. Thank you!
 
#30 ·
77'911 said:
I'd look at, initially:
1) the tsb that tazio mentioned
2) pull the plugs to see what is going on(the ends of the plugs will tell a lot)
3) check and or replace(if never done) the pcv in the crankcase vent system as it could be clogged
If it were mine, I just base line things. IE just replace the plugs, whilst checking the old to see what detonation quality is like. When replacing the pcv, I'd clean out the TB and install a bottle chevron techron concentrate($10 @ walmart) into the petrol tank(help clean the injectors). It would be a decent/reasonable idea to ohm out the coils to make sure they check out. Good luck with it, sorry to hear. Hope you get it righted.
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One could easily determine if the coil is at fault. Just swap the one from cylinder 4 and see if the misfiring cylinder follows the coil.
 
#32 ·
Amyk8323 said:
Interesting. I haven’t heard this theory yet. Thank you!
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FYI - it COULD coincide with your scenario because when a crankshaft position sensor (sometimes referred to as "CKP" or "CPS") goes intermittent, it be CAN BE when the sensor becomes warm/hot. The caveat being many times problems with the sensor trigger its own code.

If a hot sensor is the problem, it would:

1. Cause the engine to stop if it is running
2. Cause the engine to not be able to start until it (the sensor-not necessarily the engine) to cool sufficiently.
3. If the engine happens to be shut off before the heat event, the temp could rise when off (kind of like how a steak continues to cook when resting off heat) and reach the point where the sensor problem triggers, to the car could appear to fine, but unable to restart.

See caveat about CKP codes.
 
#33 ·
Just Some Human said:
One could easily determine if the coil is at fault. Just swap the one from cylinder 4 and see if the misfiring cylinder follows the coil.
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You can just ohm them out which provides definitive results. From what she is describing though, the vehicles behavior is like one where the fuel pump assembly is starting to go or the in tank filter element is starting to clog(IE result-lower than spec rest and running fuel pressures).
 
Discussion starter · #34 ·
More questions than answers: They found that cylinder 2 is leaking. Would this cause my issues?

Also, they said that my coolant pipes and hoses are leaking pink and foaming. We noticed this after the intake manifold was repaired at the last dealership. Any chance they could have damaged something in the process? They want to charge me 1200.00 alone for the coolant pipes etc.
 
Discussion starter · #35 ·
Amyk8323 said:
More questions than answers: They found that cylinder 2 is leaking. Would this cause my issues?

Also, they said that my coolant pipes and hoses are leaking pink and foaming. We noticed this after the intake manifold was repaired at the last dealership. Any chance they could have damaged something in the process? They want to charge me 1200.00 alone for the coolant pipes etc.
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See:
Image
 
#37 ·
TO ME, the pipes seem kind of pricey for what it is - it's not like they're replacing the actual valve or cooler (at least according to what's in the statement).

Interesting as they are stating the direct/port injectors for #2, seeing as it does not SEEM to be the issue of the past. Assuming it is correct, I can kind of see that price. Even good aftermarket injectors can run $300+ EACH, and they are saying BOTH direct and port, which requires removing the intake manifold (and all the junk along the way). Obviously, a lot of the steps would be done concurrently when doing both.

I'm glad I DIY though.
 

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Discussion starter · #38 ·
wty said:
TO ME, the pipes seem kind of pricey for what it is - it's not like they're replacing the actual valve or cooler (at least according to what's in the statement).

Interesting as they are stating the direct/port injectors for #2, seeing as it does not SEEM to be the issue of the past. Assuming it is correct, I can kind of see that price. Even good aftermarket injectors can run $300+ EACH, and they are saying BOTH direct and port, which requires removing the intake manifold (and all the junk along the way). Obviously, a lot of the steps would be done concurrently when doing both.

I'm glad I DIY though.
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Unfortunately for me, not everyone can DIY. 😭 The coolant issue will probably not be covered under my extended warranty. How worried do I need to be about this? Is it possible the previous dealership could have damaged the system when they did the intake manifold? It wasn’t until we picked it back up from them that we noticed all the pink.
 
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