Messy

So I keep getting 300 and 301 misfire codes. I clear them and they come back shortly after. About a year ago I had the Toyota dealer replace spark plugs. My question is number one spark plug in the front and you don't actually have to remove the throttle body to get to it? Should I just put a new plug and coil pack in one if this is the case? It cost me 250 bucks for Toyota to do the plugs, not looking to pay that kind of money again. It would appear that I do not have the skills or tools to remove the throttle body so if that needs done I would have to pay someone to do it. Maybe I should have had all the coli pack replaced but I'm sure that would have been a few more hundred dollars. Any advice would be appreciated.

mitsuguy

iTrader: (2)

P0300 is a Random or multiple misfire, p0301 is cylinder number 1... It is doubtful that spark plugs are your issue, but it is possible... How long ago were the plugs changed mileage wise??

Any other codes in the system?

It would be helpful to see misfire data for all the cylinders, if the only other cylinder that is misfiring is cylinder 6, then it is likely that coil... (Assuming you have a gs300 or is300 with the vvti motor, 98-05)... If not, which car do you have?

Messy

the plugs were changed less than 5k ago and maybe a year and a half ago. Yes it's an IS300. It starts to idle rough then hesitates and surges a little. Once the tach is over 2 k its smooth. The code is always 300 and 301 never anything else. Is cylinder 1 in the front? Can I get to it without taking the throttle body off? Should I just get one coil? And if so should I spend about $80 on a denso one or go with a cheaper aftermarket one?

Thanks for your help

sekone5

iTrader: (3)

You're not getting any other codes?It could be the coil and if it is always go with the denso or something in the same category don't buy cheap **** you don't drive a lawnmower so why fix it like one?If it solves the problem then your in the clear if not it could be a fuel problem.You're not comfortable taking apart your manifold but your willing to remove the coil pack and replace a spark plug torquing it down and making sure it's gapped to factory recommendations? Just saying it's just as hard man cause you don't want to break the plug off in the block.

14GS350F

check for oil leaking into spark plug tube

Messy

It now appears I have a leaking valve cover gasket. I pulled off the plastic piece that covers the timing belt and first two cylinders. There was oil on the plug boot. I disconnected it from the spark plug and cleaned it up cleared the code and it came back. I didn't have the socket to actually remove the spark plug but it was sitting in a pool of oil. I guess it's likely that the oil actually got down in the spark plug itself. Anyone know about how much it will cost to have the valve cover gasket replaced?