I am throwing PO 300, 301, 303, 305 codes.. obviously a misfire. I will probably just replace all 6 plugs and coils with the car at 190K. However, i need some advice on brand names. I know Denso is good, but expensive and I don't want to throw in Chinese crap, especially in the three rear ones as they are a pain to to get to. Has anyone used Spectra Premium coils out of Canada? ... Or any other quality coil brand suggestions would be helpful that don't cost and arm and a leg.

 

Hard to believe all of Bank 1 coil packs going bad at the same time.
Check any more codes, current or pending.
A/F sensor would create a misfire or even an issue with the OCV on that bank.
My brothers 99' had misfires and it turned out to be the OCV but no codes for that and just the misfires on the problem bank.

My sugg is swap the bank 1 coils to bank 2 and see if the misfires follow.
No need to take the plenum off on the 1st gens to do this.
Tight fit but its very doable.
Just let the motor cool down.

I only use OEM or DENSO (part # 673-1301) on my failed coils.
Some OEM's use Diamond Electric coil packs.
Still running 3 original coils on mine. lol

 

[QUOTE=Nad1370;10737410]Hard to believe all of Bank 1 coil packs going bad at the same time.
Check any more codes, current or pending.
A/F sensor would create a misfire or even an issue with the OCV on that bank.
My brothers 99' had misfires and it turned out to be the OCV but no codes for that and just the misfires on the problem bank.

My sugg is swap the bank 1 coils to bank 2 and see if the misfires follow.
No need to take the plenum off on the 1st gens to do this.
Tight fit but its very doable.
Just let the motor cool down.

I only use OEM or DENSO (part # 673-1301) on my failed coils.
Some OEM's use Diamond Electric coil packs.
Still running 3 original coils on mine. lol[/QUO

Thanks for all the great info.

 

If you've checked the ignition coils and confirmed that they are not the problem send your injectors to a shop to check for clogs or poor spray pattern and confirm that fuel pressure is within range.

 

+1 on previous posts and checking coils, etc.
>> If you end up in a dead end you can check your splices and hope for a hail mary.

 

also have a p0171 code... front o2 sensor? or maybe bad maf sensor? can both cause the misfires?

 

P0171 is for the rear bank air fuel sensor and yes a bad air fuel sensor can trip misfire codes and many others.

 

A MAF sensor can, but not o2 sensors.

o2 sensors usually go bad due to an engine which is already misfiring, running rich, burning oil, or simply old age

 

No air fuel sensors can do this for sure and they fail regularly on these cars even when they are running right and not that old.

 

Would that be the upstream or downstream AF sensor?

 

Upstream in the exhaust manifold. This thread walks you through it. https://www.clublexus.com/forums/rx-...el-sensor.html

 

thanks. .you've been a great help.

 

I see what your saying on the P0171 code (system too lean)
But it would trigger both banks and not just 1.
P0171 - lean on bank 1
P0174 - lean on bank 2 <-- 2001+ systems.
99-00 models only would show P0171 for lean (will not tell you w/c bank is lean, could be both)

Upstream A/F sensor
OE part # 89467-48011
Denso part# 234-9009
https://www.densoproducts.com/product.aspx?zpid=18798

 

Agree with others adding this P0171 code to the ones in the original post can the direction of the diagnostic if they all happened at once.
Any other codes plz post.
>> If you have live engine data plz post ur fuel trims, etc to see where you are at and maybe force a Lean/Rich condition and observe fuel trims to rule out bad AF sensor.

 

Yes, one bad air fuel sensor can trigger a code for the other bank even if that one is fine. So back bank can go bad and throw a code... then multiple misfire codes... code for front bank... code for temp sensor.