Hey Trevor, those plugs you took out don’t look too bad; which is a good sign. I recently replaced mine with the same NGK’s and noticed a big difference. Maybe because previous owner had Autolite Platinums??Vehicle: 2007 EX 4WD, 152K mi. I've got the ursa minor ecamper shell. Wearing Michelin cross climate SUV shoes (GREAT for PNW winters).
So the last 4 or so tanks of gas I've had abysmal fuel economy. Went from a fairly consistent average of 19.9 +/- 1 MPG to 16.3ish. No lights, car seems to drive fine but might be a little low on power. Honestly cant really tell. Trying to figure out what's going on. To give a fairly complete history, my car was in a fender bender in June (while parked, a lady hit my front passenger fender/wheel bad enough to jam my passenger door shut), and I had one tank before it got fixed returning just under 19 mpg (there was some spirited sandy beach driving involved, no surprise there). It took pretty much the whole month of august for the shop to fix it, and on the first tank when I got it back my MPG was in the low 16s. I chocked it up to helping move furniture around a hilly neighborhood for my friends for pretty much the entire tank and didn't think too much of it. The next tank, which was mostly highway miles, was around 18 mpg. Lower than usual, but not alarming. The last few tanks, which have been mixed driving, have been consistently low 16s. Trying to figure out what's causing this, because I've been super light on the throttle yet still returning the worst mpg this car has ever seen. I think the trans has been shifting a little higher than normal but not sure? Doesn't really feel like it's slipping. Could post a video if that could help people see what im saying.
What i've done so far:
-Check air filter. Looks fine, not particularly dirty.
-Drain and fill x3 + filter change on the transmission bc it's been 25k miles and the fluid was starting to get a little smelly. No metal in fluid, drain plug just had some friction material on it which is supposedly normal. Used to have torque converter shudder problem but drain and fill x3 a while back fixed it.
-Reinflate tires about 2 tanks ago, didnt see much improvement if any
-Check for brake drag. Rear spins easier than fronts, but pretty sure that's normal. Pretty much ruled out.
-Change spark plugs. 50k on them, replaced NGK laser iridiums with the same. Just did this so kind of early to determine any significant improvement. Plugs looked like this:
View attachment 212238
Believe last valve adjustment was at 101k. Kind of at a loss. Talked to a reputable mechanic over the phone and he said he wont see it without any lights on the dashboard because he doesn't want me to endlessly throw money at it. Maybe an O2 sensor going bad? Any input would be greatly appreciated! Also, let me know if there's any other information I can provide. I have a fairly complete history of this car's maintenance.
The other thing I did was to remove the throttle body and give it a real good cleaning along with shoving a lint free rag soaked with throttle body cleaner down inside where the TB bolts up and also gave that a good scrub. You’ll definitely notice a difference. I hope this works for you. Good Luck