I have a 1995 LS 400 that is misfiring and check engine light on. Mechanic read code and found P0300 Random Misfire, P0305 Cylinder Misfire, P0307 Cylinder Misfire and P0170 Fuel Trim (Bank 1). Mechanic suggested and replaced Ignition Cable Set/Spark Plug Wires, Fuel Filter, Spark Plugs and Valve Cover Gasket Set. After work was done and paid for, check engine light came back on before I pulled away from the shop. Mechanic read code and now it reads Crankshaft Position Sensor. It was end of day, I drove home and returned car to shop next morning for recheck. Mechanic says he put ina new Crankshaft position sensor but the check engine light did no go out so he put the old one back on. He is now saying I need to replace the ECM. Also, car is now leaking coolant so he says I need to replace "o" rings. Coolant was not leaking when I initially deliverred the car nor when I picked it up after the first day. Any suggestions -- could the ECM be bad? I don't know what to do nor what to believe.

SOURCE: Check engine light is on

no such thing as a catalytic computer... there is a catalytic converter ... part of the exhaust system so they may now be "guessing" that it's an O2 sensor. take the car to autozone... they will scan the codes for free.... post the codes here tho the lads and lasses there are pretty clever and will probably tell you what the codes mean.

Jim Goldsmith

• 2005 Answers
• Posted on May 20, 2009

SOURCE: engine will not accelerate smoothly and evenly, it chugs along.

Clean, inspect and, or, Replace your crank sensor or, crank sensor wiring A loose crank sensor bracket or, a start relay has caused this before

michael schultz

• 1068 Answers
• Posted on Sep 29, 2009

SOURCE: ES300 Lexus cylinder misfiring

well a compression test will tell you if the engines internal components are working properly and it is critical you start there when having a problem like this.

testing the injectors will let you know if they are giving fuel to the engine. there are two test for the injector and first one you do is an electrical test to see if they are getting turned on and off as they are supposed to and it they are internaly good electricaly with is done by listening to them with a stethoscope to see if you here the clicking sound the pintle valve makes inside of them. then there is the test to see if there spraying fuel or leaking fuel witch is called a leak down test and is done with a fuel pressure guage and a tester that will electrical turn the individual ijector on to see how much pressure it drops.

this is what i would do if i had it in my shop.

let me know if you have any more question and that you understood what i described.

SOURCE: car misfire

For the 1998 Lexus GS 300 3.0 liter DOHC

Firing Order:
1-5-3-6-2-4

Cylinders:
(back)
...6
...5
...4
...3
...2
...1
(front)

SOURCE: check engine light came on blinking< would go

he did not gap the plug wright go to some one else and have the to put the right plugs in and gap them right