I had my check engine light read and it came up with missfire on 1,2,3,4 cylinders,and running rich on the left bank.The car is a 02 WRX with 170000 miles on it.a friend was saying it was probaly the sparkplugs.

Yeah, it'd probably be best to start with the plugs as they are a relatively inexpensive fix.

I don't know, seems kind of fishy that all 4 plugs would go bad at the same time. But they are a cheap and easy fix, although I'd say the coil pack is more likely. Do you have any mods on the car?

i just got the car 3 days ago,the engine looks stock.This motor does not have sparkplug wires it has the coil on plug.I hope all the coils are not bad.

Yeah, it'd probably be best to start with the plugs as they are a relatively inexpensive fix.

 

I agree. Also since it is coil on plug I would check to make sure the coil packs aren't cracked down around the base like some of them tend to do.If that doesn't solve any problems I would second start looking a little closer at the O2 sensors.

I had my check engine light read and it came up with missfire on 1,2,3,4 cylinders,and running rich on the left bank.The car is a 02 WRX with 170000 miles on it.a friend was saying it was probaly the sparkplugs.

 

Your 5 year old car has 170,000 miles on it? That's almost 37,000 mi/yr someone was running. I'd say at the very least a general tune up is in order.

Your 5 year old car has 170,000 miles on it? That's almost 37,000 mi/yr someone was running. I'd say at the very least a general tune up is in order.

the guy i got it from drove it all over the country,he was the origional owner.i am going to get some iridium plugs for it.

I had my check engine light read and it came up with missfire on 1,2,3,4 cylinders,and running rich on the left bank.The car is a 02 WRX with 170000 miles on it.a friend was saying it was probaly the sparkplugs.

Start with a spray bottle of water. With the engine at idle spray the top of the engine mostly around the coil pack and wires, See if it skips and runs rough if it does replace the coil

the guy i got it from drove it all over the country,he was the origional owner.i am going to get some iridium plugs for it.

 

Use subaru recomended plugs, as these cars can be picky.

 

Also sounds like the car can use a tune up. Last time i got missfires on all wires was when the wires were old and wet. Replace the wires.

 

nipper

This motor has the coils on each plug ,i hope that they do not need to be replaced,i have to get the car ready to smog and get rid or the codes.

Which car is this?

i though only the newer ones had one coil per cylinder on top of the plugs. The other one has a two coil pack. One coil for two plugs using a waste spark system.

 

 

nipper

this car is the 02 wrx that has the missfirecodes,and rich on left bank.

hrmmmm

 

well there are no wires. So its either the injectors or the plugs or coils.

 

There is the possability that the o2 sensor is tired and making the car run rich.

the car has 168,000 and the guy said the belt was replaced 4 months ago,not sure when the plugs where done,ill start with them.

The rich mixture code may be due to a bad plug so changing them out is a good idea. The misfire code may be due to the wrong type of fuel or a timing issue.

isnt 168 an odd number to replace a timing belt? You may want to insepct everything under the covers.

 

 

nipper

is this a interference motor?the guy always had a shop do the work he didnt seem like the type to work on the car himself.

is this a interference motor?the guy always had a shop do the work he didnt seem like the type to work on the car himself.

 

Yes it is. Also shops DO miss idlers sometimes and tensioners. That can throw off the ignition timing.

 

 

nipper

My fix turned out to be the front 02 sensor. Here is my review from a diff thread: I have a 2001 Forester L with 85k miles on it. I have been chasing an intermittent hesitation under load problem for the past year since 80k miles. Only occurred when engine was warm. The front 02 sensor had been replaced once at 40k miles. I suspected it again this time, but since the only codes thrown had been cyl's 2&4 misfire ( p0302 & p0304) I assumed it must be ignition related. So I replaced plugs and wires 8 months ago...no effect. Did the dollar bill test over exhaust pipe, it was fine. Misted the coil, no sparks. I mentally sort of ruled out the fuel filter since it only happened when the engine was warm. Finally, a week ago while cruising on hwy at 65 mph, I felt the hesitation again (I wasn't even accelerating this time) and a new code was thrown....p0172. AutoZone read it for me, I described the symptoms to the guy and asked if he thought it might be the front 02 sensor. He said, "absolutely." So I decided to replace it next. Cost me $100.75 incl tax for the oem part# 22791aa00a from Cityside Subaru. I asked the Parts guy there if his experience was that this model engine needed a new front 02 sensor every 40k miles. He said, "no, these sensors are good for 100k miles." Well, bullsnot on that. I replaced the new front 02 sensor in 1 hour reaching from the top over the passenger side of the engine using an adjustable wrench. Be sure to use the thread lube so you can get it out easily next time.....after another 40k miles. I took out the air channel assembly first for better access. That seems to be the fix. No further hesitation since. Car runs like new.