P0301 CODE **CHECK ENGINE LIGHT**

99 Tacoma SR5 Xtracab, 3.4 V6, 5 speed manual currently with 317,800 miles.
Over the span of a month, I've made 4 trips to the dealership for a handful of EVAP codes; sensor, chip, charcoal module and some other part. Researching online tells me: P0301 indicates that cylinder number 1 is experiencing misfires. A misfire occurs when an insufficient amount of fuel is burning in a cylinder. I'm keeping the truck, so when things happen, I've always addressed them with a sense of urgency. If you've dealt with this could you share your fix?

 

Remember a code is the complete circuit not just that cylinder.

The fix depends on just what is causing the issue till you know it can get expensive to just replace all the parts and hope it fixes things

It can be as simple as a poor connection , fouled plug a bad injector bad coil or wires

you can swap the number 1 coil pak with number 3 see if the fault follows.

then you get into compression and more expense.

Can you feel the Truck miss ??

 

What a great looking 20+ year old Tacoma! If the undercarriage looks as good as the rest of your truck you are clearly doing something right. To some @Wyoming09 may have just been stating the obvious but he is spot on. There are some real experts on this site, I hope several will jump in and give you actionable advise to help pinpoint the cause. Good luck!

 

If it’s time for plugs, and coil packs I would go ahead and replace all of them with oem Toyota. It doesn’t hurt to change all of this if it hasn’t been done in awhile. Start there, see what number 1 plug looks like when pulling it out. You could have a bad plug, or coil pack. Also you could have a mass air flow going bad that can throw that code as well, which is rare but it can happen. I would change plugs, packs, and clean mass air flow sensor.

 

Before dumping senseless money into parts that might not fix your problem for a p0301, what about doing a cylinder compression test and a radiator leak down test.

5vz is known for crack heads and head gasket issue, that might be your issue.

 

A defective MAF will not trigger a specific cylinder code.

 

@Wyoming09 @saf023 @YotaDeer54 @v5ensx Turns out the plugs were worn and a bit cruddy - wheww! Labor for the plug replacement $99, "diagnostic" $99, parts $18.95 knowing I have to wait 2 to 2-1/2 hours today (appt was for 7:00 am) and paying hundreds more for fucking labor, a pain in the ass!! The manager mentioned, they ordered parts that would likely need to be replaced ahead of time so we wouldn't have to wait. I always ask for the old parts. He said it would likely be the gasket - which makes sense. It's been a slow but constant leak over time and I don't want avalanche of shit to go wrong, so I'm bitin' the bullet on this one. The dealership is and always has been my absolute last resort. Not being mechanically inclined and owning few tools sucks.

All great and spot on feedback. My mechanic is slammed for the next week and beyond. My second go-to Park Auto - same thing, booked solid. I don't want to
be stranded on the side of the road either commuting to work or running errands, so back in the shop I sit. Thanks guys - really appreciate the feedback.

 

Always good to post your location help could be near at hand if your close I am always glad to help.

Don`t you have any friends that could have helped you trouble shoot this issue and help change the plugs ??

Time to make some check out your regional forum go from there.

 

@Wyoming09 I'm in research triangle park, NC. to answer your question; I have my mechanic who I fully trust, since I bought the truck in 2004. I did have a colleague at Cisco to help once or twice; he's an engineer -and- a master mechanic, but he got a sick job offer and relocated to TX 5 months ago.

 

I don't know how mechanically inclined you are. The basic "tune-up" stuff you should be able to do yourself and save some money over the dealership. There is a lot of good info on how to fix most common issues and basic maintenance on this site. Just my 2 cents.

 

@JudoJohn to be clear, I've taken on several projects and have completed repairs and/or replaced parts for my truck on my own. This is only the second time in 17 years I've (chosen) to go to the dealership. Sometimes people prepare meals at home, and sometimes people choose to dine out.