Misfire ERROR P0300 AND P0304

[Jazz03]

Hi everyone

I've been reading other posts and I can tell this issue of misfire and MIL is so common.

The problem started after they stole my catalytic converter in day light while parked in park and ride in Oxford. Place full of CCTV camera. Called police as usual there is nothing they can do, yet they asked me to go to the council and request cctv and bring it to them.

I decided to fix the car myself so bought 2 sesnsors  and exhaust pipe and converter got them fitted locally. No issues for 6 months.

Recently misfire codes p0300 and p0304 which reflect random misfire  and misfire in cylinder 4.

Local garage checked it said o2 sensor but i told i just had sensors fitted 6 months ago as the cut them when they stole the coverter. So then  they replaced spark plugs and cleaned fuel tank and guess they reset error codes. One day later MIL showed up again.

I decided then to pay 120£ to get diagnosis from the honda dealer. They found misfire codes p0300 and p0304 which reflect random misfire  and misfire in cylinder 4. They also found brake oil leak, engine oil leak by rear seal between engine bloke and transmission. They gave me price to replace all 8 coils  1000£ plus other issues they found i.e. leaking and radiator change and converter which they thought could be a reason of misfire. Total will cost me just under 5000£.

Obviously I only went to dealer to find the issues. Because I replaced spark plugs twice in 6 months and fitted 2 new sensors and converter, the only thing I didnt replace was the ignition coils. So yesterday I bought 8 coils used of ebay taken from a running engine that had no fault. I replaced all 8 but MIL still showing so I thought I possibly need to reset the error codes. So I disconnected the battery MIL disappeared. I then took it for a drive for 10 miles and was OK 👌 so far.

Let's hope it doesn't show up again. Otherwise I'm buying a Toyota car this time. Honda full of problems

[Jocko]

Welcome. Honda dealers are just out to generate business. Don't be put off Honda by the crook you took your car to.
The most likely cause of a misfire on an i-DSi engine is a defective rear coil. I would have swapped 4 with 3 and see if the code reflected the change and if so, replaced the defective coil.
Worth having is a code reader/resetting tool. Something like this: https://www.amazon.co.uk/Autel-MaxiScan-Diagnostic-Retrieve-Readiness/dp/B07Q86G6MX/ref=sr_1_8?dchild=1&keywords=obd2+code+reader&qid=1598779419&sr=8-8



That way you can reset your own.

But don't be put off the Jazz. At 17 years old it is a great wee car and well worth hanging on to.

[Jazz03]

Thank you for your reply. Yes i need to get one. Will get one soon. The good thing is the 8 coils cost me 60£ that's why thought I'll replace all.

My question is after replacing any faulty parts in the car should the MIL disappear without reset error? Or a reset is a must following replacing parts?

Time will tell. If I drive it around for few days with no MIL means it worked. Will update you soon

[culzean]

Otherwise I'm buying a Toyota car this time. Honda full of problems

Full of problems ?  many cars would be in the scrapyard long before they got to 17 years old ... My sister-in-law has a 2002 Civic and all it has ever needed is oil, tyres, brake pads and a new exhaust  back box - now that is amazing. Before the Civic she had a string of French cars which turned into money pits at 2 or 3 years old..

[Jazz03]

I hear you.. you got a point. Let's put it that way I've been having so many issues with mine. Maybe its just my bad luck.

[Westy36]

Thank you for your reply. Yes i need to get one. Will get one soon. The good thing is the 8 coils cost me 60£ that's why thought I'll replace all.

My question is after replacing any faulty parts in the car should the MIL disappear without reset error? Or a reset is a must following replacing parts?

Time will tell. If I drive it around for few days with no MIL means it worked. Will update you soon

I've know an MIL disappear of its own accord after a few hundred miles on a previous car. Make sure your car has plenty of decent fuel in to and treat it to a proper Italian tune up.

Jocko has some very good advice. A basic scan tool is invaluable. He mentions a swop around of coil packs, good idea. The new coils you've purchased could still be faulty.

FYI: MIL is only part of the MOT test for vehicles first used on or after 1 July 2003.

Re scan tools, I understand these are very good.  https://www.amazon.co.uk/Autel-AutoLink-AL319-Universal-Diagnostic/dp/B007XE8C74/ref=as_li_ss_tl?crid=ZXKHC509DEL0&dchild=1&keywords=obd+fault+code+reader&qid=1595347368&sprefix=obd+fault+,aps,164&sr=8-6&linkCode=sl1&tag=wwwhonestjo03-21&linkId=cf2fa92b702a31841b9bf623f448e497&language=en_GB

[Jocko]

I have two scan tools plus my ScanGauge E which doubles as an OBDII device. The only time I ever had my MIL come on I was less than a mile from home, in the pouring rain, so just carried on. It reset itself after a couple of hundred yards and has never shown up again. My car is a "young in", at only 14 years old and 128,000 miles.

[Jazz03]

My jazz done 184000 miles and 17 years old

[guest334]

Your jazz is just run in, I wouldnt worry about the Dealership shopping list.
I have found improvements on the Jazz when the battery is fully charged ie via CTEK conditioner or similar - most recently when driver began using after Lock Down.
Treat the engine to Shell V Power and or Tesco Momentum full tank works best.
Good Luck with replacing the coil.

[Jocko]

Treat the engine to Shell V Power and or Tesco Momentum full tank works best.

Don't get me started. Supermarket for me and always has been. No need to waste money.

[Westy36]

My jazz done 184000 miles and 17 years old

Good to hear! 

So at just 7yrs old and 85000 miles, I hope to get many more years out of my Jazz.

[Jazz03]

I am sure you will

[DomnicZZ]

My jazz done 184000 miles and 17 years old

Mines 16 yr (sweet 16), but at 93K miles. At 3K a year, It’s hard to imagine it getting to 180K with me, but I’ll give it my best shot!

[Jazz03]

Update I kept driving the car today the MIL started flashing when at 3rd gear slow drive. So I've replaced everything so far I.e. coils spark plugs and exhaust pipe and catalytic converter.

Noticed though that when I started the car when cold the muffler rattled seems loose so my last option is to get that tightened and see.

On my way went to some showroom looking for a car thinking toyot auris or lexus ct200 hybrid.

Will see how it goes if this jazz can last me another 6 months or a year I will be greatful.

[Jocko]

Could be a loose heatshield.