2002 T4R -- shudder and loss of power

[IBobi]

Here was the original thread:

http://www.toyota-4runner.org/3rd-gen-t4rs/225499-temporary-shudder-loss-power-during-shifting.html

2002 SR5, 178k miles

Car had all 3 CE lights on for several months with no effect on driving.

A few weeks ago started shuddering at high speeds 50mph and 60-65mph. Thought it was transmission but mechanic said maybe not. He performed wheel balance and that wasn't it.

Now the car is doing that shudder at various times, even as low as 20mph. Especially going uphill. The CL lights had been cleared by mechanic, who said maybe it's the catalytic converter. They recently came back on after 2 weeks off.

Purchased OBD2 reader and got the attached codes (see photo).

P0300 Random/multiple cylinder misfire detected

P0304 Cylinder 4 misfire detected

Another mechanic suggested it could be coil packs or injector.

Another member here also said change the plugs and wires, and I have purchased the blue wires to be installed this week.

Any other suggestions, or what I should do first, based on these codes?

Thank you guys.

 

[Magmotor]

Po300

here is a step by step for checking your po300 & the po304 code. it could be several items so an in depth check for all should be done. good luck..!!

http://tacoma.site40.net/4Runner_96...2rmsour/2002/024runne/di/eg5vzfe/cip0300p.pdf

 

[sn0wrunner]

Start with the plugs and wires. Could be knock sensors too maybe.

 

[mmendelscfi]

We chased these for a while and finally flattened them by installing new plug boots on the coil pack bank side..

We did new plugs and wires but the wires only came with boots for the side they were attached to.

We were finally able to see a carbon track on one of the plugs under the coil pack so replaced the boots on that side as well.

They are an inexpensive item but they can go bad after a while

No more misfires.

 

[IBobi]

We chased these for a while and finally flattened them by installing new plug boots on the coil pack bank side..

We did new plugs and wires but the wires only came with boots for the side they were attached to.

We were finally able to see a carbon track on one of the plugs under the coil pack so replaced the boots on that side as well.

They are an inexpensive item but they can go bad after a while

No more misfires.

Start with the plugs and wires. Could be knock sensors too maybe.

here is a step by step for checking your po300 & the po304 code. it could be several items so an in depth check for all should be done. good luck..!!

http://tacoma.site40.net/4Runner_96...2rmsour/2002/024runne/di/eg5vzfe/cip0300p.pdf

Awesome! Thank you all so much!

Honestly I am just so relieved it's not the trans. I love this car and I want to drive it forever.

 

[IBobi]

UPDATE:

Mechanic installed the NGK wires and the NGK platinum dual-lead plugs 1-6.

Cleaned torque valve cover boots.

Cleaned throttle body & airflow sensor.

Running like a champ now! INcluding an oil change, oil filter and new air filter, I spent $75 on the plugs and wires, plus $260 for the mechanic. $335 all in, and these are Los Angeles prices.

Thank you guys. You were right on the money, again.

:frog: