My 99 ES 300 has had an intermittant misfire problem for almost a year now. The problem has progressively gotten worse to the point that it is undriveable.

Shortly after the car warms up, it begins to drop 2 or 3 cylinders. I have replaced all plugs and all plugs.

My local mechanic (former toyota tech) thinks I have a bad ECM.
1. Is there any way to verify this w/o taking to dealership?
2. What else could cause the loss of three cylinders at once only to work fine again after cooling.

3. If I do have bad ECM, where can I get a replacement? Dealer wants $1,800

Thanks for any advise!!

 

yeh had same problem, same dealer quote when my dad had the car, i remember changing the fuel injectors and o2 sensors

 

what codes do u have?

 

All kinds that do not seem to be related
P0125 coolant temp for closed loop
P0770 shift solenoid
P1346 cam sensor/timing belt jumped
P1133 injector
Per my mechanic all these can be ruled out because it runs fine until warmed up then it drops three cylinders at once??

 

vvti sensor for the bank of the misfires would cause a misfire on either cyl 1 3 5 or 2 4 6 depending where the misfires are causing the car to run retarded on vvti causing the p1346 to come on

 

-correction for P1133 is Air/Fuel Sensor Circuit Response. (Bank 1 Sensor 1)
http://www.obd-codes.com/trouble_codes/toyota/

 

bad coil\s?

 

yeh that could be it too, misfires happens when u dont get enough spark/fuel

 

My culprit was a leaking Fuel Pressure Regulator, an analog device so you will never know it was going bad until you swap it.

Symptoms:
Hard Start when cold or sitting for more than 30 mintues
Rough Idle
CEL P0300, P0302, P0304, P0306 MIS-Fires

 

TC P1346 VVT Sensor (Camshaft Position Sensor) Circuit
Range/Performance Problem (Bank 1)
DTC P1351 VVT Sensor (Camshaft Position Sensor) Circuit
Range/Performance Problem (Bank 2)
CIRCUIT DESCRIPTION
Refer to DTC P1345, P1350 (VVT Sensor (Camshaft position Sensor) Circuit Malfunction (Bank 1, 2)) on
page DI−134.
DTC No. Detection Item Trouble Area
P1346
Deviation in crankshaft position sensor signal and VVT sensor
(bank 1) signal (2 trip detection logic)  Mechanical system malfunction (Skipping teeth of timing belt,
belt stretched)
P1351 ECM
Deviation in crankshaft position sensor signal and VVT sensor
(bank 2) signal (2 trip detection logic)
WIRING DIAGRAM
Refer to DTC P1345, P1350 (VVT Sensor(Camshaft position Sensor) Circuit Malfunction (Bank 1, 2)) on
page DI−134 .
INSPECTION PROCEDURE
HINT:
Read freeze frame data using LEXUS hand−held tester or OBD II scan tool. Because freeze frame records
the engine conditions when the malfunction is detected, when troubleshooting it is useful for determining
whether the vehicle was running or stopped, the engine warmed up or not, the air−fuel ratio lean or rich, etc.
at the time of the malfunction.

 

Thanks for the suggestions. Still working the problem.
So far I have repalced the ECM, Coils, and Plugs.
Symtoms still the same:
After engine warms up, it begins to miss until all three cylinders on the side nearest the firewall begin to miss.
Considering replacing the vvti cam position sensor next? Anybody got a repair diagram for that one?

 

Get some freeze spray, and when the engine starts exhibiting the symptoms, spray the various electric/electronic components that you suspect. Hit the suspect component(s) with a very quick burst of the spray. Restrict the spray to a single component at a time, not a large area. Frost may form momentarily, but will quickly evaporate.

The quick burst will lower the temperature of the component quickly, and will allow you to determine whether you found the culprit.

If it is caused by a component, than you should be able to identify it prior to randomly changing parts.

Phil

 

research oil control valve issue

 

Well I just wanted to close out this thread by saying that after A LOT of trial and error including new coils, a used ECM, new plugs, vvti sensor checks, I finally stumbled across the culprit... a malfunctioning (not inoperable) Oil Control Valve on the firewall side (R) of the engine. My suggestion is to disconnect the electronic connection from the OCV with engine running to see if this improves idle. Because my OCV was malfunctioning rather than inoperable, the piston in the OCV was oscillating erratically causing the missfire. By unplugging the connection, the OCV will not work at all and the engine should idle smoothly! An easy and inexpensive way to rule out a bad OCV! Only wish I had known this earlier. Thanks yeskay!

 

So, bought the little 99 es300 and it wouldn't smog b/c of random misfires in bank one. Replaced coil on cylinder 4 (long story) and the oil timing valves (both banks). Drove it a bit and it was great, and smogged. But within 200 miles, developed a misfire on cylinder 4, but only at idle or under load, and NO CODES. Note: If I idled above 1500RPM, no misfires. There were two clues to the solution: (1) no codes. All the other "misfire" solutions are related to codes. No codes, but misfire means it must be something that doesn't code; and (2) under load - which to me means timing. So, I pulled the elec for the fuel injector, and the misfires continued, but with NO CODE. THen, I pulled the cam position sensor (which feeds data to the ECM which uses that data to make the fuel injectors work) and it looked good and tested good (in resistance range), but it was a little varnished. cleaned it super shiny, put it back, and viola... all is well with the world. If the cam shaft position sensor isn't always reading the accurate cam position for cylinder 4, it misfires with NO CODE. I'm ordering a new one (mine seems a little sensitive to me) for $30 on line. I hope this helps others. I will say this... if you get misfire codes for an entire bank, do NOT go to the O2 sensors or MAF until after you've cleaned and/or replaced the oily parts (cam position sensor, oil timing valves). I have a great Solus Pro ODB reader. Because it was able to give me feedback while operating, I was always able to determine that all the sensors were fine (notwithstanding all the threads that say to blame the O2 sensors) while the misfires (code and non-code) were happening. I even got o2 codes from the oil timing valve problems, but I knew the o2 sensors were okay. Once I stopped getting the codes, but still getting the misfires, then it all fell into place. Good luck to all. This misfire issue is a real mess.