Hey guys and gals,
I’m a first time poster here but have been browsing the site for advice. Anyways, I’m caught in a bind on this issue. The backstory of my RX was it needed valve cover gaskets replaced and was waiting for time off from work to do it. The Alternator died out in it around mid December of 21’. It sat in my driveway til March when I got time to replace the valve cover gaskets, spark plugs, alternator and battery. Once it got done, it started up fine and left it in the the driveway til I could get time to get it inspected. The next time I started it is is misfiring and developed a transmission problem.
I put a scanner on it, which showed b2s1 was bad and getting the P0300,P0302, P0304, and P0306. So I replaced the O2 sensor, and drove it to the transmission shop to take a look at it. It sat there for a week only to be told they couldn’t do anything because it is misfiring badly. I got it home, scanned it again, and got the Same codes with now an added P0303. And nothing else. I looked at some live data with the scanner, the O2 sensors are working, and the MAF is working like it should, at this point I’m at a loss at where to go, but would had to throw parts at it with the hope it fixes something.

I I’m not sure if this is dealing with the cam position sensor, coil on plug wires, vvt solenoid or something else like ECU.

anyone have any solutions to try or look at?

thanks

 

Welcome to Club Lexus and your 1st post!
+1 for telling the story with detail.

How would you rate yourself for DIY repairs, beginner, average, etc.

Reason I ask is because you will have some diagnostics to do moving forward and need a scanner which you hopefully already have and a multimeter too.
Hoefully others have ideas too.

 

I would ignore the 303 for now since it was a late arrival.

You didn't mention how it was running before you changed the valve cover gaskets and plugs.
Did everything go back where they came from? All wires, grounds, and hoses reconnected?
Did you use OEM plugs?
Did you try clearing the codes and seeing what comes first?

 

I would rate myself as skilled, above average below professional . Have a scanner and multimeter as well,

 

sorry about that. The car ran great before everything, no issues even was in the process of getting it inspected. The only thing that stopped me before getting these things done was the alternator gave up the ghost and the car sat for a little over two months before I started to even tear down into it. Everything that I know went back to normal except the hose loop that goes in the back of the intake manifold. Any hoses that were removed came off of the intake and accessories, I left the vacuum block alone.

I have tried clearing the codes but they just came back.

the spark plugs I used were denso iridium, from rock auto. Upper intake manifold gasket was replaced with a mahle gasket.

 

Forgot to add that before all this I had no warning lights on the dash, except for the airbag light, which most likely is the clock spring has broke.

 

Can you clarify "Everything that I know went back to normal except the hose loop that goes in the back of the intake manifold"?

Well, it was running fine before the work, seems likely something went awry there. Trouble areas are:

• Ignition system
• Injector
• Fuel pressure
• Compression pressure
• Valve clearance
• Valve timing
• Air flow meter
• Water temp. sensor
• Open or short in engine wire
• Connector connection (very vague, guess this means any connectors)
• Engine ECU

At least bank 2 is right up front. Easy to do a compression test, swap coils, check coil wiring, verify spark, check the fuel, etc.

Also: what "Transmission problem" did you develop?

 

This is the part I was referring to. Connects to the back of the upper manifold. Holds a tube, thinking one of the ac lines traveling back.

Also when I mean the RX was running good before the work, I mean you could put a scanner on it and only come back with driver side air bag.

I checked the air meter, even took it out and sprayed it down with mass air cleaner.

on my scanner, I was able to do a live data sweep. O2 sensors are looking good, you can see the voltage rise on the air flow meter when you give it gas, at idle and while driving. Afr on both banks at idle are reading perfect 1.0 lambda +/- 0.1. Didn’t get a chance to see what the afr was while driving.

I was thinking possibly the coil on plug wires, or cam position sensor is slipping, with the cam sensor I would assume it would have flashed a code.

the transmission issue started after the work was done and started to drive it. It shifts hard in first like I got a shift kit on it, slips half way through second and briefly goes into 3rd and goes into forth. I can turn off o/d to go into 3rd so I’m not lugging in 4th. Before this it was shifting smoothly took me to work everyday with out a hiccup.

the only thing I did with the tranny was replace the filter, and gasket and refilled with Toyota Type-T 4

 

Pull each plug out and see if the tube is full of oil?

Valve cover fix, has to deal with valve tubes and if they leak, you get oil in the spark-lug down hole.

Other than that, you may look for disconnected electrical connectors.

Also check the 12v dc. You may have spikes on it causing strange behavior.

Salim

 

Great posts already.
Can you plz post up your fuel trims too.

Like to see Long Term and Short Term fuel trims at idle with AC off and engine fuly warmed up.

 

when I did the valve cover gaskets, I did replace the ring gaskets as well that go over the plug holes.

when I get time I’ll need to check electrical connections again.

 

I can do that be give me a little time on that request. It might be two weeks before I get that posted here. Work, side jobs and vacation are coming up

 

Check all grounds. I had something similar happen to me on my 2002 Highlander. Did both cover gaskets and changed the transmission oil cooler hose. When I finished the car by the end of the day, I went for a drive and was horrified when it wouldn’t shift gears and barely ran. Multiple misfires code came on.

It ended up being the ground wire that goes on the back of the intake. Best of luck!