So my 2000 V6 is throwing some codes and running rough. I don't have them on me but there were 4 and were p300 301, or something like that. I am due for a spark plug and ignition wire change so I am doing that. Getting the NGK plugs and wires. I know there are only 3 wires, so I was wondering if there are any other parts I should be doing as well. I'm guessing I start with these and then go from there if needed?
Replacing Ignition wires and plugs. Any other parts?
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NorthShore4Runner
New member
Could be fuel injectors in cylinders 1 and 4. Could also be bad fuel filter or fuel pump.
Take the plugs from 1 and 4 and put them in different cylinders. If the misfire follows the plugs, swap all the plugs and problem solved. If not, it's probably a fuel system issue.
Take the plugs from 1 and 4 and put them in different cylinders. If the misfire follows the plugs, swap all the plugs and problem solved. If not, it's probably a fuel system issue.
TheDurk
Elite Member
Plugs 1 and 4 are on the same ignition coil (the front one), so that becomes a prime suspect, along with both plugs and the wire to number 4. Inspect both plugs and resistance test that wire when you change them. It's a series circuit, so any open knocks out both. A short to ground will knock only one. Fixing a problem is good, fixing it and knowing the cause is even better.
If plugs and wires don't do it. then swap the #1 coil with another and see if the misfire moves. If it does, replace the coil. If it doesn't, start thinking injectors.
You can also confirm spark circuit is good by holding the end of plug wire 1/8" or so from the block (FSM approved).
Below is attached in case you do the plugs and wires yourself. Avoids lots of screw-ups having it at hand.
Attachments
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AZ4Running
New member
Start simple pull the plugs if they are fouled, damaged or have a huge gap replace them and see how it runs. Be sure to get the correct type plugs, twin electrode oem type plugs only. Check for spark by pulling each plug wire/coil put a Phillips screwdrive in the end of the wire, touch the screwdriver to any metal on the engine and have someone crank the engine. There will be a strong spark if the coil is working, be careful the spark is strong and will gibe you a good zap. If you have a spark tester even better. If all these are good and you still have misfires then look to the injectors. A fuel filter is good to do along with the plugs and wires as is a fuel system flush and engine decarb.
Thanks for all the answers guys. Is the engine decarb the Seafoam motor treatment? Tried to search decarb and only got 5 hits...
AZ4Running
New member
Yeah seamfoam work pretty well. Valvoline intake cleaner works even better and ac delco sells one that is really good also. Remove the evap line from the intake manifold and SLOWLY add the seafoam as the engine is running. The line you removed will work well to add the seafoam just put one end in the can and the other to the maniflod pinch the line so it goes in slow. You want to add it slowly over about 5 minutes. Notice how many times i used the word slowly. Then take it around the block to blow all the crap out, lots of white smoke will come from the exhaust. You can also put a small amount in the gas tank to clean the injectors a little.
Well the spark plug and wire change made it run nicely for about 5 miles, then started getting jumpy again and the CEL came back on. I will do the decarb this weekend, but it is looking like the fuel injector more and more, huh?
19963.4lsr5
New member
You need to follow the above post on troubleshooting your misfire codes. Seafoam will not solve a misfire and carbon buildup will not cause a misfire by itsself.
With cylinders 1&4 giving codes it's most likely a coil breaking down or you need the boot kit and replace the boot for the coil on #1. Or check the icm connector on that coil.
I swapped the 1 and 3 boot, and then cleared the codes. Took it for a short drive and threw a P0301 P.
TheDurk
Elite Member
Just the boot? Why not the whole coil?
Sorry, I think it was the whole coil. The whole piece that bolts into #1.
TheDurk
Elite Member
Yeah, that's the coil. The boot is just the rubber piece that covers the plug.
So looking like injector.
If I am still getting the 301 and 304 is that consistent with a fuel injector too?
TheDurk
Elite Member
Did you do the spark test suggested above? If so, and you have swapped wire, plugs and coils, then you have ruled out ignition, despite the fact they are on the same circuit. You should confirm spark, though. So after ignition, it's fuel, compression, timing or crank/cam sensors (plus the last resort--bad ECM).
So fuel is next on the list and injectors (two of them) are where you start. One approach is to remove them all and send them to witchhunter.com for cleaning and testing. Mark the 1 and 4 and put them back somewhere else. They all could probably stand a good cleaning. Misfires can be a real pain to track down.
A new fuel filter and a fuel pressure test are good things at this stage, too.
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