mintymonty

hey everyone i own a 2004 TL with a manual trans. i’ve been having misfires on all 6 cylinders. i’ve replaced spark plug o rings, valve gasket seals, cleaned egr and intake, cleaned maf sensor, and then i did a valve adjustment. after the adjustment and all this i was still getting misfire codes for all 6 cylinders. but now it says a code for a faulty rocker arm, i then did a compression test and my highest psi was 240 in cylinder 1, 125 in cylinder 2, 70 in cylinder 3, 135 in cylinder 4, 40 in cylinder 5, and 150 in cylinder 6. could this be result of a bad valve adjustment. i think i made them a little tight now that i think back. also i have replaced spark plugs and all 6 coils. could this be a bent or burnt valve? the car starts but runs rough and shuts off while driving sometimes.

peter6

Compression is all over the place. Either valves are badly adjusted or bent or something happened to compression rings on the pistons. Did you touch timing by any chance? What code exactly?

Adjust valves again following the procedure in service manual and check compression again.

Since you have manual, was engine over-revved?

mintymonty

thanks for the reply man, i did not touch the timing at all and the codes are p0300 p0301 p0302 p0303 p0304 p0305 p0306 p0420 and p2646.
engine was not over reved since i’ve owned it but a 17 year old high schooler used to own the car before me so maybe. thinking about going back and trying to adjust the valves properly. or should i just go and have a shop look at it and see if it’s a bent valve or something. i’m right on money and trying to use all my cheaper options first. thanks again!

El_Cheapo

I agree with Peter6. Compression is all over the place.

Check that all the timing marks match. You can also do a leak down test to see where it's failing.

mintymonty

thanks for the reply, i’ll check timing and do a leak down test today

cammark35

P2646 seems uncommon. what oil are you using? can you see any signs of sludge build up? for instance, when you remove the oil fill cap is everything coated in dark goo or golden to golden-brown oil film?

P0420 along with misfires on every cylinder.. I would focus on primary O2 sensors first. also the condition of the pre-cats. if you think the sensors are original, probably worthwhile to go ahead and replace them, clear the codes and see what happens. I think you can see the upstream side of the catalyst matrix on the front pre-cat if you unscrew the sensor and point a small flashlight in. may be able to get an idea of it's condition visually.

justnspace

iTrader: (1)

it's a 6MT, chances are that it has been over-rev'ed are HIGH!

since compression is not consistent across all cylinders, the next step is leak down test....or one can skip that and just remove the heads to check for damage.