Engine Miss-fire

[bloodlust]

A few weeks ago i started my car at work to let it warm up and when i got in to leave, i put it in drive and the idle dropped to approximately 600rpms and it started to shake like it was gonna stall. I didnt have any more problems with that up until 2 days ago when it started again and now its not going away. When you cold start the car it runs close to 2000 rpms then it drops to 1000 when its warmed. But once i put the car in drive it drops to 600-650 and it shakes a bit. You can also hear it in the exhaust like its running on 5 cylinders. I did a bit of research and ive removed and cleaned my IAC valve. There was no change in performance. But once i pieced it all back together and started it, it threw me an engine error code, which it hadnt done previously. The print out from the computer was "Cylinder 1 Missfire". Now my next step is to change my plugs but could this also be a bad injector? Would that also give the same symptoms ive experienced? Any thoughts?

Edit: Exact from OBDII printout

"

DTC (Codes)

P0300

Random/Multiple

Cylinder

Misfire Detected

P0301

Cylinder 1

Misfire Detected

DTC Pending (Codes)

P0301

Cylinder 1

Misfire Detected "

The only thing that worries me is that it didnt throw a code until i pulled it apart and cleaned that valve. So im wondering if the error code is from the initial start up when i put it back together.

[92Lex]

Have you checked the spark plugs? It seems that the codes are pointing to a problem within cylinder #1. Maybe the spark plug gap on the first cylinder is off. But honestly, don't solely rely on a code to help you solve the problem. The codes you're "pulling" is only an aid to the diagnostic process.

[bloodlust]

ive changed the front 3 spark plugs. i didnt have time to do the back 3 because of work. there wasnt any change in performance when i changed the front 3 so im assuming that cylinder 1 is on the backside of the engine. i will update after i change the back 3.

[bloodlust]

ive changed the front 3 spark plugs. i didnt have time to do the back 3 because of work. there wasnt any change in performance when i changed the front 3 so im assuming that cylinder 1 is on the backside of the engine. i will update after i change the back 3.

sry for dbl post

but i changed the back 3 plugs... no change in performance. i removed the wire from cylinder 1 spark plug... no change at all. plugged that back in and removed plug from injector... no change at all. im definitely getting spark cause i felt it shoot up my arm when i pulled the wire off. so my next step is to change that injector.

[anthonyiez]

ive changed the front 3 spark plugs. i didnt have time to do the back 3 because of work. there wasnt any change in performance when i changed the front 3 so im assuming that cylinder 1 is on the backside of the engine. i will update after i change the back 3.

sry for dbl post

but i changed the back 3 plugs... no change in performance. i removed the wire from cylinder 1 spark plug... no change at all. plugged that back in and removed plug from injector... no change at all. im definitely getting spark cause i felt it shoot up my arm when i pulled the wire off. so my next step is to change that injector.

lol!!!

sorry don't mean to laugh but spark shooting up your arm isn't a diagnosis for if the coil or wire is good. try switching the coil with another cylinder and see if the miss moves with the cylinder.

[bloodlust]

lol!!!

sorry don't mean to laugh but spark shooting up your arm isn't a diagnosis for if the coil or wire is good. try switching the coil with another cylinder and see if the miss moves with the cylinder.

i know how to properly check for spark. and i did that. i was just stating my very first observation... lol which was the jolt that went up my arm.

but anyways i changed out cylinder 1 injector and its running fine. thanks for all the help guys. ...1 tank of 87 octane = bad...

[Toysrme]

Bull*BLEEP*.

[bloodlust]

Bull*BLEEP*.

explain please

[92Lex]

I think Toysrme was just trying to finish your sentence.

[anthonyiez]

lol!!!

sorry don't mean to laugh but spark shooting up your arm isn't a diagnosis for if the coil or wire is good. try switching the coil with another cylinder and see if the miss moves with the cylinder.

i know how to properly check for spark. and i did that. i was just stating my very first observation... lol which was the jolt that went up my arm.

but anyways i changed out cylinder 1 injector and its running fine. thanks for all the help guys. ...1 tank of 87 octane = bad...

not what i ment. how can you tell if a ignition wire/boot is shorting to ground in the sprk plug tube while its not hooked up. just because spark is making it the end of the wire doesn't mean its making it to the spark plug. sorry i'm just a trained technician/owner who specializes in toyota/lexus and honda/acura trying to help out. just keep tossing parts eventually you can fix any problem.

[92Lex]

I must agree with you anthonyiez, taking the shotgun approach isn't the best approach. But I think bloodlust has already figured out what was wrong with the car. Who knows, maybe a DSO was used.

[anthonyiez]

I must agree with you anthonyiez, taking the shotgun approach isn't the best approach. But I think bloodlust has already figured out what was wrong with the car. Who knows, maybe a DSO was used.

i have to disagree on the dso though. the concept of owning one is actually diagnose a car not to use it to load the shotgun :D

[bloodlust]

I must agree with you anthonyiez, taking the shotgun approach isn't the best approach. But I think bloodlust has already figured out what was wrong with the car. Who knows, maybe a DSO was used.

i have to disagree on the dso though. the concept of owning one is actually diagnose a car not to use it to load the shotgun :D

i pulled the end off the plug and put a screwdriver in the boot and watched the spark arc over an inch off the screwdriver to a nearby piece of metal. (not the safest way to test but still a test).

...after rereading your post a few times i finally got what you mean. and thats a good point. your suggesting that it could have been shorting inside the boot and not actually firing the plug. but luckily that wasnt the problem. just the clogged injector. and i wasnt mocking or turning down your help. i appreciate everyones input.

anyone care to explain this "shotgun approach" you speak of?

Edit : also just figured out the "bull *BEEP*" ...ok you caught me... a few tanks of 89 also.

[92Lex]

"Shotgunning" is when you assume everything else is okay and replace a part right off the bat, without testing all other components. A lot of incompetent mechanics do it. That's why some customer's bring their cars back multiple times, only to have more parts thrown at it. If you had an auto technician working on your car....it'd be different.

[bloodlust]

"Shotgunning" is when you assume everything else is okay and replace a part right off the bat, without testing all other components. A lot of incompetent mechanics do it. That's why some customer's bring their cars back multiple times, only to have more parts thrown at it. If you had an auto technician working on your car....it'd be different.

i see. im not a certified mechanic (obvisouly) but i do have some experience in the field. so i guess i just narrowed it down as best i could and then replaced what i thought was not working. ill try to be more cautious next time to test every possiblitly before i actually buy parts. allthough i definitely needed plugs anyways...

[92Lex]

Its really not a big deal. It's not expected that a typical DIY'er has access to all the correct tools and perform the proper diagnostic methods. Acceptable at home but definitely, unaccecptable at a shop. At least everything worked out for you though.