Hey guys I think I am having a small misfire on my 01 TL-P. There's no check engine light, and I've run a scanner on it with no codes and no misfire data. I changed my spark plugs with NGK plugs back in January 2011.

Is there anyway possible that one of the coils could be bad/weak and not setting a DTC?

Symptoms:
- At idle the car seems to idle a tad bit on the rough side and every once in a while you'll feel like the engine misfires on 1 cylinder quickly.

-MPG are sub par at 19-20mpg.

-Car has 169k and the valves were never adjusted. Do you think adjusting the valves would help?

 

done the egr port system cleaning yet?- needed every 75kmiles -those clog with exhaust carbon and causes symptoms you describe
Simple under 2 hour `at casual pace` DIY

and YES!!!!!!!!!!! adjust the valves,,a few to several are tight and a few are loose by now
use a GO-NO GO feeler guage for accurate results first time

used correct ngk for your engine?--type S different heat range
and they were the 8 buck each platinum or iridium/iridium ix??

 

make a day of DIY with valves, egr in intake manifold, service the TB- IACV idle control on bottem of it
that takes advantage of overlapping labor on parts removal to access other part

also lube the throttle cables entirely, and the TB throttle return spring assembly

have you seafoamed the gas tank and vac port--that fixes many things related to carbon buildup

 

note: I would seafoam the oil and change oil and filter before valve adjust-
you want the rear sealing edges clean so accurate setting is obtained

169 and never done internal cleaning?--install new oil filter- add 1/2 can seafoam and drive 100-200 miles
change oil and filter with oil warm

 

the coils are easily damaged during plug change- do you remember setting one down hard on the workbench? that will do it a few months later
A weak/damaged coil may not throw a code yet- but these other items need to be addressed in diagnosis,,are they done or still needed

 

EGR port cleaning and Thermoblok spacer going on in the next couple of weeks.

And as for the NGK plugs, I used the ones that were like $3. Not the platinums. And yes they were for an 01 Tl-P.

I'll try and do my valve adjustment this summer when I have free time at work.

Yeah I seafoamed the vac port and gas tank yesterday.

I just changed my oil the other day, so I think i'm gonna wait til the next oil change to do this...

I took them out, and gently placed them down on the cowl area of the car. But I will try and take care of everything else before I go ahead and replace the coils. I will test the coils when they are out during the valve adjustment.

 

no reason to spend 300 on coils you dont need!!

WHEN you are ready to do valve adjust, seafoam the oil- it will clean the areas you will be working,, so no sludge residue to mess up the measurement

the 3 buck plugs MAY FIT but ARE NOT the approved and correct plug for our system!
you really need NGK Iridium, Iridium IX or the stock Platinum which I think cost more than Irids now!
But get those plugs out today and the correct parts in- it will return to smooth running
You may feel slight changes as seafoam does its thing thru gas

 

Hmmm ok thanks!

I just did my Thermoblock spacer and cleaned the IM and EGR out today. I was speechless when i saw the amount of crud that was in the intake manifold.... It looked like no one had touched it since 2001 when the car was new..... =( But I got it all cleaned up and it runs like a champ!! But I still need to change out the plugs to the NGK Iridium plugs next sometime.

Thanks for the advice!

 

Also forgot to add that the car starts up almost instantly now! Before it would take more than normal time to start up for a car.

 

thats clogged egr system

 

yup. I should have taken some pictures of how bad this thing was....

Car drives strong now! Changing plugs to the proper ones this week!

 

Well changed the plugs to Irridium IXs yesterday and the car runs smoother, but I still have a slight shaking at idle. You can barely feel it, but it's there. My 02 Accord 4 cyl had this same exact problem, and I could never figure it out. Maybe I need to adjust my valves...

 

that will make a differance for sure--fuel injected cars like precise spec setting

also did you clean the TB air plate,,and iacv/ Idle air control valve- on bottem of TB unit

 

how is the front motor mount?

 

yup when I cleaned the IM, I cleaned the Tb and everything in it.

I think one of my mounts is worn because when I turn off the car, I feel a vibration. When I pull out my transmission this summer to rebuild it, I will inspect all the mounts.

 

front mount tends to go early as 60kmiles! get under the car and look for oil trail from mount,,strange small drip on driveway under radiator?

front and rear are vac boosted and oil fluid filled!!,,a bad one causes mystery vac leak and engine miss

iacv- on bottem of TB, you removed the cover and the actual rod that rotates- cleaned the `air slit` in the rod and cleaned the chamber it rides in?

 

yup cleaned all that.

Everything is dry under the car. So either all the oil has leaked over previously before I owned the car, or they are just worn... I'm gonna go ahead and replace the mounts though in the summer.

 

you can do the normal- buddy holds brake while revving in D and R while you watch for engine movement

 

Ive done all modifications on my 99 tl. When my car is warmed up I turn it off and then turn it back on. It idles below 1k. Almost turnig off and sometimes it does turn off. Then after a few seconds to a minute it goes back to normal. I've done erg Port cleaning thermoblock spacers, replace all coils and spark plugs with Ngk platinum back in summer 2010. Also Replace front and left side mount. I HAvent done a valve adjustment yet and my car has 101k mil.

 

Also seafaomed the car a couple of times Before every other Mod two summers ago and that seemed to have work but it would come right back a few months later.

 

on the egr port cleaning- you removed the intake manifold from the engine and worked on it on the bench.. to poke a wire rod thru the manifold length ?

and the TB/throttle body- flipped it over and cleaned IACV/idle air control valve--its a tube with slit for air to go thru--gets clogged bad = bad idle air control~

seafoam gas tank: 1 can to half tank every year
do that twice, or do gas plus vac port (or thru TB) once a year

100kmiles and 11+ years,,I would get the tools out for a valve adjustment!!
You may even find the intake manifold bolts loose after the thermoblock install-
they do loosen slightly-enough to make it run funny