Question about 2001 Toyota 4Runner

Open Question

1997 4Runner 4wd, 6cyl Limited. Engine running rough. replaced plugs, wires, coils, fuel filter, and computer and still runs rough. I discovered codes on invoice of P0300 and P304. Have paid a lot of $$ for this and now I need help.

Posted by on


6 Suggested Answers


6ya staff

  • 2 Answers


Hi there,
Save hours of searching online or wasting money on unnecessary repairs by talking to a 6YA Expert who can help you resolve this issue over the phone in a minute or two.

Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.

Here's a link to this great service

Good luck!

Posted on Jan 02, 2017



  • 2 Answers

SOURCE: rough idle

check you throttle position sensor first then fuel pressure regulator, then fuel pump. i have a 92 and had to recently do a massive overhaul. my rough idle was caused by a malfunctioning tps with a small exaust leak causing it to race and an intake manifold gasket. also check your idle speed adjustment settings.

Posted on Dec 03, 2008


ash seder

  • 166 Answers

SOURCE: 2000 Camry 4 cyl 2.2L.

sounds like you have a problem with the spark the coil may be on its way out or there may be oil in the spark plug holls shorting out the spark.
your best bet is to pull the leads out 1 at a time and and look down and check for oil if there is oil there get a new rocker cover gasket.
if no oil refit plug leads loosely and start the car remove one lead at a time slowly and look at the spark cumming out the end off the lead is it blue? if so it is ok if it is yellow and dull you have a coil problem. also check that the spark is only coming out the end of the lead as it may be coming out the side of the lead and shorting to earth,
you can do this by slowly moving the lead around the top of the spark plug holl and see were the spark is coming from

be carfull no to shock your self as it hearts like hell

good luck

Posted on Jan 01, 2009


  • 125 Answers

SOURCE: 2000 Toyota 4 Runner, 3.4L, 6 Cylinder. Engine

look at the plug wires they are known to bust when old near the boot

Posted on Apr 30, 2009


  • 118 Answers

SOURCE: 1990 Toyota Pickup

carb or Fuel injected try cleaning either one of these bad distributor cap or rotor or distributor good luck

Posted on Sep 24, 2009


Timothy Barnes

  • 2 Answers

SOURCE: 1995 Toyota 4Runner. 4WD

I had the exact same problem and after reading all of the advice on the internet (mostly saying "bad o2 sensor") and changing out every sensor imaginable, distributor cap, rotor, spark plugs, plug wires, air flow meter, fuel injectors and harness and every other "fix" I had read about, I took it to a mechanic. $1000 later and a new valve to replace the bent one and my 4runner runs like new. Which for the sluggish 3.0 isn't saying much anyway. Point being that I probably threw 1000 bucks worth of new parts on it before I actually took it in and got the problem taken care of. Save time and money and take it to a pro or pull the engine apart and check the valves yourself.

Posted on Apr 26, 2012

Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

1997 4Runner Limited 4wd, auto, 6cyl. Engine running rough. Replaced plugs, wires, ignition coils, fuel filter, and computer .... big bucks and still running rough. I and the Technician need help! On my...

First the DTC P0304 is a misfire on number 4 cylinder which would be a sparkplug,plug wire,coil or a fuel injector and sense you've replaced three out of the four I would think you have a clogged or faulty injector.As for the DTC P0300 that is a random misfire detected which could co-inside with the bad injector.If it were me I would replace the injector and go from there and see if that fixes the problem.

Oct 06, 2013 | Cars & Trucks

1 Answer


it was related, ignition system..
you have to check ignition coil(pack).
improper distribution engine runs rough.

May 27, 2013 | Cars & Trucks

1 Answer

2002 pontiac grand am se1 6cyl is idles rough

what mileage,spark plugs,fuel filter[,coils module,this #1]

Feb 22, 2013 | 2002 Pontiac Grand Am SE

1 Answer

91 Explorer 6cyl XLT standard is super hard to start, the engine sounds muffled when starting and while running, quickly overheated once it was running, looses power when pressing accelerator.

Could be a clogged catalytic converter. It could also be a bad head gasket allowing some coolant to enter the cylinders. Check for milky grey oil.

Dec 18, 2011 | 1991 Ford Explorer

3 Answers

Why is my 1986 toyota pickup running rough

Thanks for choosing FixYa and welcome to the site. There are a few things that can cause a vehicle to run rough. First, check for vacuum leaks. A simple leak can cause a car to act up. Make sure the air filter and fuel filter are not clogged up. If you haven't had a tune up in a long time, it may be that. Replace spark plugs, coils, distributor cap, coil packs. Make sure no wires or hoses have come loose. Check to make sure your pcv valve is not clogged or broke. You might want to flush your coolant as well. Go ahead and change your transmission fluid and filter as well. It is possible that you have a sensor going bad also. Try to pull any codes off the computer that you can. If you can, it may lead you to the root of the problem. If you have any questions, feel free to ask and thanks for using FixYa.

Apr 12, 2011 | 1986 Toyota Pickup 4WD

1 Answer

1995 ford f150 6cyl - runs rough when cold. Then

Check the coolant temp sensor (the one that speaks to the ECU) which acts like the choke on a old carb type engine. These can be tested with a multimeter by dunking them in different temp water.

Feb 02, 2018 | 1995 Ford F150 Styleside Regular Cab

1 Answer

Engine runs very rough

if is runnig the PCM is not the problem,change the coil pack or the crancshaft position sensor.
the PCM is very expensive(500+) but they hardly go bad. PCM(power control mudule)

one more thing,have you tried the spark plug wires?

Sep 08, 2009 | Chrysler Voyager Cars & Trucks

3 Answers

Runs rough when a load is put on the motor.

chiltons or haynes manual found at any parts store

May 23, 2008 | 1994 Ford Explorer Limited

Not finding what you are looking for?
2001 Toyota 4Runner Logo

169 people viewed this question

Ask a Question

Usually answered in minutes!

Top Toyota Experts


Level 3 Expert

85222 Answers

Colin Stickland
Colin Stickland

Level 3 Expert

22485 Answers

Jonah Oneal

Level 3 Expert

14092 Answers

Are you a Toyota Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides