2004 Acura TL. 6sp with no navi.
176k.
New NGK OE spark plugs

I recently bought this car and drove 2k+ miles across country in it. When I bought it it did not have a CEL. on the Trip and CEL came on checked the codes, random misfire. I attested it to bad gas. Put in fresh 93, seafoam, CEL goes away....The comes back, same codes, then disappears. Keep in mind this is all highway miles, so RPMs in the 2-4k.

Now im back home, change the spark plugs. Lots more stoplight/stop-n-go traffic. Now, my CEL comes back on, and is BLINKING while I am stopped. Blinking means it is misfiring so much, the unburnt fuel can damage my catalytic. Ok, lets play find the misfire by unplugging the coils. I find that disconnecting ANY of the front 3 cylinders has any affect on the motor running. Ok, lets swap out the coils to see if it follows the coil. NOPE, disconnecting any of the front 3 coils still does not have an affect on the engine.

Any ideas?

 

what brand coils did you replace with??



may need a compression test to determine if the head is good

 

his troubleshooting is suspect.

if no change in engine note when unplugging the coils, it points to those coils...
furthermore; didnt even attempt the rear coils?
odd troubleshooting is odd.

 

Maybe I wasnt clear. I changed the front coils with the rear coils. I did not buy/add in a coil. The non-reaction did not follow the coil, but stayed with the cylinder.

 

i'm still lost.

- engine on
- unplug coil pack/cylinder 1 (rear left)
- does engine note change? yes/no?
-if yes, plug coilpack back.
- move on to cylinder 2. unplug coil pack... Does engine note change?
- if yes, plug coilpack back.
- move on to cylinder 3. unplug coil pack. Does engine note change?
- if yes, plug coilpack back.

 

- unplug coil pack/cylinder 1 (rear left)
- does engine note change? yes
- unplug coil pack/cylinder 2 (rear middle)
- does engine note change? yes
- unplug coil pack/cylinder 3 (rear right)
- does engine note change? yes
- unplug coil pack/cylinder 4 (front left)
- does engine note change? no
- unplug coil pack/cylinder 5 (front middle)
- does engine note change? no
- unplug coil pack/cylinder 6 (front right)
- does engine note change? no

now, scramble the coil packs, and the answers above will still be the same.

 

Could be a clogged cat maybe?

Don't want to be the bearer of bad news but I had similar issue when I got my TL & the compression was toast on all 3 front cylinders. Ended up replacing the motor.

Oh and.. why would you go across the country to pick up a car with 170k?

 

perfect! thank you!
that was test one!
now to move to test two and three..

perform a leak down and compression test.

 

So you are saying the harness to the front 3 coil packs is having an issue?

 

Thats what it appears to be. One thing I didnt think of was take out the coil with a spark plug in it and see if it sparks near metal. Like the older distributor style testing spark. Also wondering if I can test the voltage at the coil plug.

Ill do a compression test.

 

Just remember, it might not be a misfire. The computer is programmed to see an increase in power when a plug fires, and it if doesn't see that increase it sets the light. Might be lean, vac leak, injector, etc

 

Did the coil pack with a spark plug test and there is spark, so its not the harness.

Did a compression test and this is what I found.

Back of engine

125...120...170

120...80...105

Front of Engine.



Really low and really high. You guys think wacked out valves could cause this?

 

ok, just read. Do the compression test again, but put some oil in there and re-test.

Any type of oil?


Justinspace - I imagine a leak down test would tell me, but I dont think Autozone has one of those to rent.

 

did anybody ever solve his problem i’m having a similar issue with my misfires in my 04 tl 6mt. i had a misfire on every cylinder along with a leaky valve gasket and spark plug tube seals leaking into spark plug well. so i adjusted valves, replaced all gaskets and seals, cleaned egr port and sensor, cleaned throttle body and upper intake manifold, changed spark plugs and tested coil packs and the all are perfectly fine. put it all back together and cleared cel. waited for it to come back on and now i’m still misfiring on every cylinder. except cylinder 5 is okay now for some reason it’s misfire went away but the rest stayed. also i have a code now p0420. the car has 220k miles. anybody fixed this misfire mystery?

 

I had a similar problem, I did a video about it if you want to check it out,