engine problem?

so recently i noticed my motor running a little strange. its a 2.0l motor. anyway, i was pulling up to my class and my teacher heard my car and told me to pop my hood. he said it sounds like a cylinder is skipping or not hitting right. and he told me to sit in the car and rev it and when the rpms came back down...we both noticed a little vibration as the rpms came down. its my first subaru so i dont have any idea how they drive or anything so i just thought thats how the motor is but my teacher says they are usually very smooth running motors. so somehow i gotta figure this out. im gonna put a scan tool on it and check out the power balance test. other than that i dont have a clue. anyone have any ideas for me? possibly king wrx? ha

 

Any CEL's? I am guessing not.

 

what year is it? any engine management?

 

Year mileage?

 

no engine managment. 2005 wrx with almost 50,000 miles. here are the symptoms: when i shut the car off it shakes the whole car (all wrxs, or just mine?) gas mileage blows. a little vibration when revving and rpms come down. kind of hesitates for a split second when tearin ass.

 

ohh and no CELs

 

could be a gas leak? i know 02-03's get them in the winter time. not sure about 05's

 

well there is no sign of a gas leak. and i dont smell gas or anything. i guess ill figure it out when i get the power balance test done tomorrow.

 

Any mods like intake, hows your idle, any fluctuation?

 

nope no intake modifications. motor is completely stock. and the idle seems fine...like i said i dont know any different cause this is my first boxer motor.

 

I doubt its has gas leak, and if it does, its not what you are thinking. I got a 02, and i hate winter. My car smells like a freaking gas station. But the leak in the 02-03 during winter time don't affect performance of the car at all.

I think.

 

Does it rattle when you reve it up an rpms drop? Waht does your oil look like and is it low? Have you had your spark plugs changed or any of your regular maintenance done?

Other than that i would need to take a look at it in person....

 

I was just about to say check/change your plugs.

 

The shaking when you turn it off is normal....crappy soft as mush stock engine mounts. Mine and both of my buddies cars did that until we upgraded to GroupN mounts.

Are you sure the teacher isn't mistaken the unequal length boxer pulse for a misfire? Many mistake that for a misfire.

 

engine oil is fine. just changed it not too long ago. and i have never changed the plugs and i have a feeling the previous owner has never changed them either. My teacher could be wrong but out of all the techs ive seen he is haus at diagnosing an engine problem so i believe him. and now that he said something i notice it to...except the pulsing noise cause i thought thats just how subarus sound. the thing i notice the most is when i rev it and as the rpms drop the car has a slight vibration at a certain point. i put valvoline synthetic blend 5w-30 in it after it having conventional.

 

Pull all the plugs and put a fresh set in, drive the car for 20 miles and pull the new plugs, be sure to mark them which cyl they came out of. Once you have them all out lay them all together and make sure they are the same color, and shade.

You may have a leaking injector thats gone bad or one light injector... the plugs should show it though.

 

and if it is a leaking injector/light injector i guess i just replace it? and what will the plugs look like if i do have a bad injector?

 

^^

By looking at his post, if all 4 are not all the same shade, than it might be an injector. Test that, he knows what his talking about.

 

The plug that will show the leak would be a lighter color than the rest, showing that it was lean.

 

ordering plugs online is a lot cheaper than plugs from the dealer so im gonna order them. i noticed they sell one step colder. is that bad for a motor thats not tuned? i am getting an accessport soon hopefully if the sell goes through with a member on here. id just be running stage one for a little while though.

 

took my car to subaru of kennesaw and they said nothing is wrong with my car. i know its not running too smooth so i guess im just going to do regular maintenance like change plugs and i was going to clean the pcv system. maybe it will run a little smoother. the tech said it pulls great but i know something still doesnt seem right.

 

i have the exact same problem... accelerate then let off the gas, then there is a big jerking motion when the rpms come down.. i thought it was the motor that was trying to catch momentum back (and due to the softness of the engine mount it amplifies the effect through the cabin), but other wrx's and sti's i`ve driven do not do that haha so i figure something is wrong with mine... it seems to be worst in 1st gear, and that makes me think its the engine mount? i dunno hope u fix your problem and tell me what you did to fix it cuz it sounds like we have a similar problem.


i do smell a LOT of gas in my car though.. i have a catless downpipe, but more so than ever before, and i seem to be getting white smoke from under the hood sometimes along with my coolant running out so often.

but yea dont mean to hijack the thread but thats what i`m going thru.

but then again my car has 135k miles

 

i dont smell gas at all. but i do go through it like hell. and the coolant thing....check your dipstick and take a lighter and light it. if it pops and sizzles you have coolant in your oil and if it burst into flames (over exaggerating a little) then you have gas in your oil. and yea i guess im gonna replace my engine mounts sometime soon. im waiting for a kid on here to get back to me on an accessport as well. anybody think a 3inch straight pipe could be throwin me off a little? cause thats what i have.

 

well, when i looked at the car i checked the roughness monitor all cylinders read 0 for misfire.
i drove the car, the car seems stock except for a straight pipe as stated before, and for a stock wrx it seemed to pull just fine and didnt have any hickups or jerking while driving it. the only thing i noticed was the regular boxer engine shake that they all have at idle and with the straight pipe you can really hear the unequal lope of the engine that someone new to subaru might mistake as a misfire.

if the car seems to be slower or lacking in performance than it used to by all means do the regular maintenance things that should be done anyways, it can never hurt.

best of luck and let me know if you need any further help in the future

 

thanks a lot kingwrex. i appreciate the help. never hurts to get it looked at i reckon ha

 

I had the same issue when my car was stock until I got the access port and a tune at Top Speed. The factory tunes are based on epa regulations and fuel economy not necessarily performance. A pro tune will really smooth out your motor guaranteed. By far the best first mod.