JPI Racing

You have to know the RX300 is a little bit different. It has the individual coil. I'm not a big fan of swapping parts. Find the problem and then fix it. Your long and short fuel trim will tell you.
JPI

Lexmex

It is, but not my much. I certainly wish I could have gotten and RX coil down here (but no Lexus in the entire country) and Toyota is the only alternative when you need your car and can't wait a week for parts.

radhead25

I took my 99 rx300 with 100k to IRA lexus in Ma for rear brakes change. After driving out of the dealer parking lot, the check engine light comes on and the car was trembling. I was furious and have a mindset that the technician might do someting to the car. It is strange because the car was fine before bringing it to service for brakes. My question is "What are the symptoms of an engine coil being broken?" The only thing I can think of is that they might disassemble the battery and reset the brake light cause the brake light was on. I might be wrong. I just don't trust IRA lexus technicians anymore.

JPI Racing

This is a non related item. Your brake was on because it's low on fluid or the brake resevior sensor isn't working. There aren't any brake sensor on the RX300 unlike Ls400 and Ls430. Any part would fail at any moment. We were testing drive an Is300, the vehicle die. Come to find out, the MAF(Mass air flow sensor) fail. Is it our fault? Absolutely not.
JPI

mikey00

There is a small chance that something like the MAF failed while they were doing your brakes and as mentioned it's really not there fault if it did. I believe there is a much greater chance that while servicing your car they did other rountine checks and caused the CEL. A common one is that when they check the air filter, they lift up the top of the air box and disconnect the hose behind it where it connects to the metal tube below. This is located directly under brake fluid container.

Lexmex

I replaced my Camry coil to the regular RX coil last night and the car runs somewhat smoother and not as loud. However, the Camry coil worked when I needed it.

JPI Racing

The hose under intake come lose won't cause your vehicle to run bad. It's part of the evap system, if it does come lose. Your check engine light will be : P0440, P441 and P0446. We've seen many Lexus tech made this same mistake in the past.
JPI

rwilson2

OK, I've read through this thread and I honestly can't make heads-or-tails out of most of it.

My '99 RX300 is getting (consistently) a P0305 code, which says that cylinder 5 is misfiring. I can feel in running rough. So, I figured - what the heck, put in some new spark plugs and see if that fixes it up. Of course, to get to the back cylinders, you have to take the entire damn top of the engine apart (air scoop, throttle, etc.), but I was able to handle all of that.

I got in all the new spark plugs, and (just in case), moved the ignition coil from the front-right cylinder to the back middle cylinder (assuming that cylinder 5 is the back-middle cylinder - or at worst, the front center cylinder). No joy!

I still get the P0305 code, still runs rough.

So, I have 2 questions: 1) which cylinder is #5? (Please - oh _PLEASE_ tell me it's at least the one on the right side if it's still in the back); and 2) what else could be causing a misfire on a specific cylinder? (Please try not to use too many acronyms and jargon, I'm new to "modern" cars... I could disassemble a carb, or even replace a head gasket on my old cars, but the new stuff is still "magic" to me.)

JPI Racing

We'd need to know your Long fuel trim, reading on your MAF(Mass air flow sensor) at idle and 1900rpm and the reading of your A/F(Air fuel sensor). There will be bank 1 and 2. Bank 1 located by the firewall. Here are the order of cylinders on Bank 1: 1, 3 and 5. So #5 would be the last one on your right. If you are not familiar with the new electronic, I would have an independent lexus shop or Lexus dealership have a look.
JPI

rx300toro

i just had my timing belt done and two days after I got my truck back ... I started to experience a cylinder misfiring problem. So i took into Lexus and at first they check the air flow meter but it was fine and then they were going to try replacing the P1135 air/fuel ratio sensor to correct the 1/3/5 misfire in bank 1 ... now they're telling me that they took off the cover and performed a vacuum test and confirmed a low steady reading of 15-16 ... should be around 19 ... this low reading would indicate retarded timing ... they went further to say that they suspect that the rear cam is out by 1 tooth and that they recommend to remove the belt and re-align at a cost of approximately $500 - help!!! I'm not sure if they're being honest in their diagnosis or just capitalizing on an opportunity to squeeze me for more money! If anyone can help, I would really appreciate the input.

Lexmex

It would be interesting if you could run an OBDII scan to see if any other codes pop up. If you are getting cylinder misfires you certainly would have gotten some other codes.

JPI Racing

Hello there,
Most of the time the inexperience will miss a tooth in the rear when doing timing belt service on this vehicle. What is the code?
JPI