Hi,
I have a 2007 Acura TL 3.2, 153000 Miles, Automatic transmission, recently got the car, it had some misfires in cylinders 5 and 6. I inspected the spark plugs and ignition coils, turned out it had 2 bad coils, so I changed them with new Delphi coils, the next day engine light came on again now I have misfire in cylinders 1,3,4,5 and 6, I inspected all spark plugs and coils all of them seem to work fine, so at the moment I am not sure it's either spark plugs or coils. However, I am planning on changing all the spark plugs with new NGK ones this weekend. since it wouldn't hurt.
what could it be? should I run ATS fuel cleaner, or maybe change the EGR valve, should I use only premium gas? I am kinda lost.
I don't have any other codes, and the car usually idles roughly when I start it, but shortly after it gets better.
Also, how old are air and fuel filters?
Live data only detected misfires in cylinder 6, all of the rest were 0
air filter looked good like it was replaced recently. Haven't checked fuel filter as I believe it's inside the gas tank.
What do your fuel trims look like?
long trim 0% both banks
short B1 -2.3%
short B2 -10.9%
and detected misfire in 3,5,6
should I run ATS fuel cleaner,
Worth a shot I guess. Not much to lose. Probably won't do anything though.
change the EGR valve
I don't think this would cause misfire only in certain cylinders
should I use only premium gas?
no that would fix pinging not misfire.
As the FAQ suggests, try swapping coils and injectors around and see how the misfiring responds.
I appreciate your help, already tried swapping coils, cylinders 5 & 6 for example still has misfire even after new coils and plugs, that's why I was thinking something else just don't know what exactly, I ordered OEM new plugs going to replace them all this weekend and see, I think they're due anyways.
Tried spraying some brake cleaner to see if there's a vacuum leak but didn't find anything,
I also added the ATS cleaner like an hour ago, going to see if it does anything.
Again Thank you for the help, any other advices would be appreciated.
Tried spraying some brake cleaner to see if there's a vacuum leak but didn't find anything,
that's a quick and dirty test, but definitely not good enough to rule out vacuum leaks. Be careful with brake cleaner it dissolves plastic.
https://www.youtube.com/@scottykilmer/search?query=vacuum%20leak
Thanks.
+1 for changing the fuel filter (if equipped) and checking fuel pressure.
A lot of Honda products require periodic replacement of the fuel filter.
I am planning on testing fuel pressure after I do some other tests, There's no fuel filter in this model, just a pump and the sending unit assembly.
The misfire is effecting both banks. I would check maf , map, iat and engine coolant temp sensor. Whatever is wrong isn't isolated to one side of engine. Most likely it has to be something that effects both sides. I would check out the sensors I just listed. I would f focus on the mass air flow first . If all that checks out pressure test the fuel system. Just throwing this out there did you double check you reinstall everything properly after changing the 2 coils.
Thank you for the help, however, won't any of these sensors trip a code?
I did double check the install, the wiring and tried swapping coils and plugs, I am also suspecting its something other than the plugs and coils because of the misfire is not consistent, for example I scanned the codes today and the misfire is in 3,4,5 and 6.
I will check the sensors and clean the MAF tomorrow and see what happens.
It only will throw a code if the failure rate meets a certain criteria. With a mass air flow I think it will throw a code if it drops below 20 to 30 percent from normal operating range. I don't the the exact numbers for your car but I should be ballpark around the same
Thanks. I will inspect it and clean it with MAF cleaner.
Using a scan tool with live data simply drive around and graph the sensors. Look for any drop offs or high random spikes . The maf at running temp in idle is should be similar to the size of the engine in g/s. If it's off by points that's not a big deal. The map in kpa measurement will be the same as outside pressure . You can go on any weather app and pull that info. Again if it's off by a small amount it's not a big deal. It has to be done while driving and at idle, that is the only way to get accurate information. There are a lot of videos out there you can watch that will show step by step on how to graph and read it.
This is very helpful. I will look into it. Thanks a lot...
Have you checked the spark plug WIRES? They can fail too after time- the car is about 16 years old. And yes, this car uses unleaded premium fuel - 91 octane.
Wiring, coils and sparks are all good checked them and double checked them.
Does using regular fuel cause misfire in this case? I don't know the history of the car, but i filled it twice with regular fuel...
Not usually.but might under hard acceleration. Higher octane fuel helps prevent pre-detonation in high compression engines. KInda like turning a gas engine in to a diesel when high compression fires low octane gas.before the spark plug does and makes that knock sound because it ignited out of time. Today's high tech computers in cars can sense the type of fuel that's being fed the engine and adjust timing accordingly. An '07 may not be capable or sensing octane. I suggest using high octane 91 as recommended by the manufacture.
There's no fuel filter in this model, just a pump and the sending unit assembly.
Every gas or diesel car has a fuel filter. In your case if there is nothing else it's part of the pump assembly and likely needs to be changed after 17 years and over 150K miles.
I think that's what he meant