First of all, I am a newbie so excuse me if this is the wrong thread, or if I am providing redundant information......
I have an '02 MDX w/ 93K and got a dreaded MIL & VTM4 light about a month ago. When I read the codes (using a generic OBDII reader), I got multiple misfires. I cleared them and continued to drive and got multiple misfires again a few days later. (This time different cylinders, but both times it was four different misfire codes)
The only drivability problems I noticed were a slight shutter under light throttle load at approximately 1500 RPM. The shutter was most notable in 5th gear at about 50 mph.
Stumped, I read these forums and started on my pursuit to repair. Like any wise do-it-yourselfer mechanic, I started cheap by checking the battery and found it only had about 400 CCA. Thinking this could cause insufficient voltage to the coils, I replaced it and reset the codes. (It needed it anyways.....just let me keep telling myself that.) No fix.....same codes came back a few days later.
Next, I changed the sparkplugs and air filter and reset the codes again only to have them come back on again a few days later.
By this time, I had researched this forum extensively and decided my next approached involved more costly parts and/or labor. (possible EGR valve, or o2 sensor, or valve adjustment.)
EGR valve was the cheapest, so thats what I bought. When I replaced it and reset, I got the same codes again within 10 miles.
I was soooo perplexed by this point that I finally broke down and called my dealer...which is what I should have done to start with!
While I was describing my problems to them and answering some of their questions, I learned that my wife had been running 87 octane fuel in our MDX for the last 45,000 miles!!!!
My dealer told me that it was definitely clogged EGR ports. They continued to tell me that it would cost me about $350 to have them perform the service. They also told me that if I had the mechanical aptitude to change a light bulb then I should do the job myself and save the $$$.......they even offered to give me the TSB to do it with.
I went straight to the dealership, got the TSB and a bottle of "top engine cleaner".....when I asked about the gasket needed, they told me to be careful with the old one and save that $$$ too!!!
I took the TSB home, and in about 30 minutes cleaned the EGR ports (which were not "just dirty"....they were "CLOGGED") and ran the top engine cleaner through. After another code reset my MDX runs PERFECT again... No more codes and my mileage has gone from 18 MPH back up to about 25 MPG. LIFE IS GOOD!
I am not going to get into detail about how to clean the EGR ports because I think it is covered in either this thread or another, but I will say it was practically as easy as changing the oil. I anyone needs pointers on how to do it, let me know.
Hopefully this information helps someone with the same problems I had.....
A couple of final notes.....
1. My wife now know that our mdx REQUIRES premium fuel.....
2. I have a practically "brand new" EGR valve for sale listed in
the classified forums.
3. I dont know if my computer ever gave an "EGR insufficient
flow" code because I did not have the Acura specific codes in
my generic scanner, and the dealer told me to save my $$$
and not hook it up to their scanner.
4. BIG KUDOS to Kendall Acura of Eugene, OR and Honda World
of Coos Bay,OR for their help.
Lastly, we will be in the market for a new vehicle again soon, and thanks to the helpfulness and professionalism of the two dealerships listed above our new vehicle will DEFANITELY be a Honda or Acura.