river

Just bought a 2000 RX300 AWD with 195000 miles getting 16 MPG. After getting lot of advise on this forum how to improve gas millage started with putting new air filter and cleaning MAF.
Put the new K&N lifetime filter and cleaned the MAF installed on the hose, later read it has to be removed from hose by two screws. I have a question
1. do I have to do it again by taking it out of the hose?
2. when I was cleaning the MAF I saw some traces of oil in the hose going to engine. Is it normal or it is indication that need new PCV valve.
Thanks in advance for your help.

Roop10

M.A.F. 1 Side of the Amber diode which shows the build up, i used CRC M.A.F. cleaner ($8.50+tax @Autozone) and it cleaned it right up




Cleaner side of the Amber Diode, still cleaned this side as well




Down inside the sensor are 2 little metal wires, i believe diodes as well, the one on the right was dirtier as you can tell it's not shining like the one on the left, the cleaner made this looks brand new again, just give it time to air dry




Bank1 Sensor1 Air/Fuel Sensor, replaced with a new one and car finally started driving normal again, this caused it to be in limp mode. Denso Part # DENSO 234-9009, seen on amazon for $92, however it says made in china, the one i have says assembled in USA but maybe its parts are made in china as well, i dont know but i bought it at autozone for around $120-150, i cant remember because i bought it last year thinking it needed replaced before but it did'nt, RockAuto has it for $117.79+shipping

Roop10

Just make sure you spray the sensor with some penetration spray and let it sit for a little bit, i used Sili-Kroil, worked like a charm, broke lose right away, put anti-seize on threads of new sensor before installing, make sure not to get any on the sensor. Also i raised the front of the vehicle and was able to get back far enough to reach the sensor better from the front of the driveshaft area

Roop10

And now my gas mileage has went back to normal 25-28mpg

river

Thanks
what about oil in the hose?

Roop10

Oil in what hose?

Roop10

I took the 2screws out of the MAF, otherwise you cant get it clean if you dont take it lose from the air intake. Im not sure about the oil part of it

river

oil in intake hose, one side is connected to air filter/ MAF other side going to engine. I saw some trace of oil there. My question is do i need PCV valve fpoor this.

Roop10

I'll have to check into it, mine has around 194k, I haven't thought about checking the hose but i do need to check the PCV valve. Please post if you happen to find out before me lol

hsmac

cleaned my pcv valve today. lexmex's instructions were a bit too brief for a newbie like me and I had to spend some time analyzing and researching before I could get it out. looking at a picture of the valve helped, and helped me understand that it was not a screw on like i thought it was due to how secure it was. the space was also extremely limited and someone with big hands might have a difficult time with this task.

first thing to do is unclamp the hose and move the clip off the valve. then you want to pull the hose off (direction should be away from you if you're facing the car). once the hose is off, grab by the handle and pull the valve upwards. ideally it should pop out but mine was really tight and it took some effort. i had to pull really hard and wiggle it back and forth until it finally came out. you may use a screwdriver to wedge it loose from the grommet first if you're careful. i wasn't sure how dirty it was or how well of a job i did cleaning it since it seemed like no matter how much cleaner i sprayed the cleaner would still come out mildly brown, but it was definitely cleaner than before. had i known how cheap they were, I would have just bought a replacement beforehand. putting it back was a lot easier using a flathead to press it back down into the hole.

6.0PSD

Going by the dash screen reading, I'm getting an amazing 9mpg driving mostly in town. Can't imagine how much lower mgp's it would get if temps were lower here in NJ and I had to warm it up longer... Last tankful got me about 145 miles with less than 1/4 tank left. I just fill it back up with 92/93 octane and pray fuel prices don't go back up anytime soon.

hypervish

I'd suggest calculating the mpg the old fashioned way, and getting a true reading.

There's something seriously wrong if you are getting 9 mpg, either mechanical or your right foot is glued to the floorboard. I've gotten better than that stuck in gridlock traffic in NYC.

The worst mpg I've gotten all winter thus far in NJ is 16.4 MPG, I'm usually hovering right around 17.0 - 18.0 mpg all city. (all hand-calculated figures)

6.0PSD

I think injector(s) may be sticking for one but have not had any codes as of lately, which I am happy about... I do tend to be heavy footed every now and then, but only when all fluids have had plenty of time to get to operating temps... Been running 92/93 octane since I owned it and currently running with a can of gumout system cleaner to try and help... Think my fuel eco issue started when I dumped about 12oz of lucas upper cyl into near empty tank before I drove 4 miles to my favorite fuel station, it started misfiring then threw a bunch of codes, had loss of power... That is why I think the overdose of lucas caked tips of injectors... It's been about 400 miles and it is slowly getting power back... @9mpg is probably a little better than 400 miles ago which I barely got 100 miles on tankful... After lucas incident I have seafoamed it cautiously three times and been jumping around between berryman, seafoam and gumout system cleaner in the tank every fill up and definitely have been feeling the power slowly come back, hesitation seems to have been eliminated in this last tankful... I have new oem plugs ready but will wait till late spring to change.

fastnoypi

i think the lucas treatment loosened up carbon deposits and gunked up your plugs. Your injectors are most likely fine, but if you suspect them of being clogged get them professionally cleaned, prices start at $25 per injector to be flow tested and cleaned. Being in NJ, this winter fuel isnt helping anyones mpg.

ssgi4in12

Thanks everybody for your contribution here. I recently bought a 2002 rx 300 from cars2africa.com . So its the european model with 46,000km on the Odo. I use it somewhere here in Nigeria with mostly city driving with traffic sometimes. I used to have the low idle problem the first time i drove the car about 2 weeks back, and had to scan with autel scanner to see the following codes p0420, p0505, p0174. After following the direction to clean IACV, the only code left is p0420. But i recently discovered that there is a little leakage on the exhaust just before the oxygen sensor after the CAT under car. Could the little leak trigger the p0420?

Presently my MPG is around 11MPG and its most city driving with average speed of 15km/h. The other time I made a highway trip, I got around 18mpg on the car nav display. And the fuel we use here is regular unleaded wof about RON91.

What other things do i need to do to improve the fuel consumption.