97 Park Avenue code P0300

[jamesmdx1]

I have a 97 buick PA just over 200k, I just changed the front valve cover gasket, and front 3 spark plug wires (rear was changed a few months ago) without any issues and car started and ran smooth. There was some oil on the exhaust manifold and just underneath is a small heat shield, was burning the oil off a little so I shut engine off and let cool down a bit. I sprayed some water with the hose in between the heat shield and the manifold to clear out some of the oil and crud.. sprayed underneath and in the front of the radiator and condenser. I let everything dry and the next morning went to start car and started running rough and CEL blinking and got a code P0306... later on i check the wires and made sure they were tight on the coils and everything looked fine, cleared code and tried again and the same code... i checked all the wiring and now I'm getting a code P0300 .. I'm thinking something happened after I cleaned the bottom of engine with water but not sure what it could be.. I ordered some new GM coil packs .. I figured i'd change them since they are the originals.. I was reading it could be the crankshaft position sensor but not sure that could be it ... never had any issues driving in heavy rain or going through puddles...

 

[BuickGirlFromMars]

I have a 97 buick PA just over 200k, I just changed the front valve cover gasket, and front 3 spark plug wires (rear was changed a few months ago) without any issues and car started and ran smooth. There was some oil on the exhaust manifold and just underneath is a small heat shield, was burning the oil off a little so I shut engine off and let cool down a bit. I sprayed some water with the hose in between the heat shield and the manifold to clear out some of the oil and crud.. sprayed underneath and in the front of the radiator and condenser. I let everything dry and the next morning went to start car and started running rough and CEL blinking and got a code P0306... later on i check the wires and made sure they were tight on the coils and everything looked fine, cleared code and tried again and the same code... i checked all the wiring and now I'm getting a code P0300 .. I'm thinking something happened after I cleaned the bottom of engine with water but not sure what it could be.. I ordered some new GM coil packs .. I figured i'd change them since they are the originals.. I was reading it could be the crankshaft position sensor but not sure that could be it ... never had any issues driving in heavy rain or going through puddles...

thats an overreaction to buy coil packs.....

so.... do you have a misfire monitor on scan tool? What cylinders are misfiring on the counter, when you get enough misfire the PCM will start collecting a cylinder count for each
Otherwise, do you won a test light and did you EVER dielectric grease your plugs? you left out that detail so Im worried

 

[jamesmdx1]

from what I read the most common cause for that code is failing coil packs, car has always run very smooth and quiet this only happened after water was sprayed on the lower engine. yes spark plugs and coils got dielectric grease and a little boot grease.
i dont have a scan tool I just have a small code reader.

 

[BuickGirlFromMars]

from what I read the most common cause for that code is failing coil packs, car has always run very smooth and quiet this only happened after water was sprayed on the lower engine. yes spark plugs and coils got dielectric grease and a little boot grease.
i dont have a scan tool I just have a small code reader.

What do you mean by plugs and coils got dielectric AND a little boot grease
what grease have you put into these spark plug wires?

code reader = scan tool
For not much you can get a scan tool
but you read the common cause of P0300
did you know ICM, vacuum leaks, carbon, Cat converter, cross fire, carbon tracks, bad crank balancer, etc can cause this?

 

[jamesmdx1]

What do you mean by plugs and coils got dielectric AND a little boot grease
what grease have you put into these spark plug wires?

code reader = scan tool
For not much you can get a scan tool
but you read the common cause of P0300
did you know ICM, vacuum leaks, carbon, Cat converter, cross fire, carbon tracks, bad crank balancer, etc can cause this?

Like I said the car ran flawlessly after finishing the valve cover and the new wires … started fine and had running for at least 20 min … until I rinsed the lower engine after it cooled down .. so something got wet that probably shouldn’t have ..started it 36 hours later and that when it ran rough and threw the code
I used a little dielectric grease and a small amount of boot grease to prevent the boots from getting stuck on the spark plugs
yes I read the common causes of 300 code .. I have the factory service manuals .. Icm, coils, CRankcase position sensor, cam sensor .. etc .. I can eliminate most of the other stuff because there wasn’t any issues with the car prior to the rinsing of the lower engine ..never had any ignition issues ..
I have checked the wiring to the crank and cam sensors and both look good when unplugged as well as icm wiring and ground ..
I just have a code reader, I want to purchased a scan tool tablet that I can also use to test sensors and that I can use for programming etc.. willing to spend $1,000.. on it but not sure what one would be the best.. would come in handy because we have a total of 18 vehicles ..

 

[jwadee87]

for personal use something like this might be fine Autel MK906BT Wireless Bidirectional Car Diagnostic Scanner OBD2 Coding TPMS for sale online | eBay

but for someone servicing many many vehicles as a business I don't know.

I have had the code p0300, Random, Multiple Misfire Detected. Car was shaking and running a little rough, you could tell there was a performance issue.
In my case, I had replaced all 3 coils, even though one was bad. because.. you should optimally.
one coil pack was bad, no sparks. (you could probably replace the bad one and be fine, but I did all 3 so I won't have to do the others in the future or make any stability issues with any of them.)

Have you tried pulling off all coil wires, and having someone crank the car and see if one of those 3 coil packs don't spark? then you can investigate further to determine if it's a coil or the ICM.

it could be something else, I don't know but I am just sharing what I have been through.

 

[jamesmdx1]

for personal use something like this might be fine Autel MK906BT Wireless Bidirectional Car Diagnostic Scanner OBD2 Coding TPMS for sale online | eBay

but for someone servicing many many vehicles as a business I don't know.

I have had the code p0300, Random, Multiple Misfire Detected. Car was shaking and running a little rough, you could tell there was a performance issue.
In my case, I had replaced all 3 coils, even though one was bad. because.. you should optimally.
one coil pack was bad, no sparks. (you could probably replace the bad one and be fine, but I did all 3 so I won't have to do the others in the future or make any stability issues with any of them.)

Have you tried pulling off all coil wires, and having someone crank the car and see if one of those 3 coil packs don't spark? then you can investigate further to determine if it's a coil or the ICM.

it could be something else, I don't know but I am just sharing what I have been through.

Thanks for your advice .. I have 3 new gm coil packs and went ahead and bought a new GM ignition module I got a good deal on them .. I figured the car has just over 200k and all that is original so I’m sure it wouldn’t hurt to replace all… will get around to doing it tomorrow or Wednesday and let you know how it goes … do you use any dielectric grease on the coil terminals ? Or any heat sink grease on the module ? Thanks

 

[jwadee87]

Thanks for your advice .. I have 3 new gm coil packs and went ahead and bought a new GM ignition module I got a good deal on them .. I figured the car has just over 200k and all that is original so I’m sure it wouldn’t hurt to replace all… will get around to doing it tomorrow or Wednesday and let you know how it goes … do you use any dielectric grease on the coil terminals ? Or any heat sink grease on the module ? Thanks

I didn't use any and it's working just fine, but I have seen Rainman Ray's Repairs on youtube do that before on a car, in a video. I don't think you need to though.

 

[BuickGirlFromMars]

Like I said the car ran flawlessly after finishing the valve cover and the new wires … started fine and had running for at least 20 min … until I rinsed the lower engine after it cooled down .. so something got wet that probably shouldn’t have ..started it 36 hours later and that when it ran rough and threw the code
I used a little dielectric grease and a small amount of boot grease to prevent the boots from getting stuck on the spark plugs
yes I read the common causes of 300 code .. I have the factory service manuals .. Icm, coils, CRankcase position sensor, cam sensor .. etc .. I can eliminate most of the other stuff because there wasn’t any issues with the car prior to the rinsing of the lower engine ..never had any ignition issues ..
I have checked the wiring to the crank and cam sensors and both look good when unplugged as well as icm wiring and ground ..
I just have a code reader, I want to purchased a scan tool tablet that I can also use to test sensors and that I can use for programming etc.. willing to spend $1,000.. on it but not sure what one would be the best.. would come in handy because we have a total of 18 vehicles ..

Explain what boot grease is, please, Because It sounds like you may just have grounding out spark before your plug and thats causing it to run rough. Where did you direct the water, and how much pressure? Did you cover the ICM/battery?
if you want a good obd2 reader that does a LOT of vehicles, a MK808(i have this model) was an excellent deal albeit it slow sometimes, it was cheap and it does about everything a tech 2(Which you can buy a tech 2 clone for about the same price, only does 1991-2012 ish GM vehicles) right now to me it sounds like ignition wire-to-plug-grounding out. if you remove each plug and inspect the ceramic on the front of the engine, do you see dark lines on the ceramic?

 

[BuickGirlFromMars]

Thanks for your advice .. I have 3 new gm coil packs and went ahead and bought a new GM ignition module I got a good deal on them .. I figured the car has just over 200k and all that is original so I’m sure it wouldn’t hurt to replace all… will get around to doing it tomorrow or Wednesday and let you know how it goes … do you use any dielectric grease on the coil terminals ? Or any heat sink grease on the module ? Thanks

If you want to help the new ICM and Coils, clean the aluminum heat sink(the bracket) they mount on so that its aluminum(the hazy aluminum is actually a mineral called aluminum oxide, terrible conductor or heat) when clean, using a Heat paste that you use for a CPU on a computer is adviseable, to facilitate transfer, but even using Dielectric grease is better than nothing since it should keep the aluminum from corroding.
On the towers of the coils, you should only use dielectric grease like you do on the plug wire end for the plug. A light coating on the rubber boot (nothing on the metal part) so that it creates a seal where it meets on the coil around the base part to keep the spark going between the metal and not grounding out outside the wire. Same concept for the plug end. thats why i was concerned you have "boot"grease and dielectric. You only need dielectric and you should have it on the boot.