hey Guys-

I bought a 99 SE auto with 103k from the original owner. As soon as I bought the car I've replaced the spark plugs with NGK Oem Laser Platinum plugs, drained and refilled the tranny with Nissan D-matic, chaaged the air filter, but was unsuccessful at changing out the fuel filter.

I drove the car for a few days and all seemed swell. yesterday in the morning, I tried starting the car but it was having a tough time starting. the engine would turn over but would not start. I then gave it a little gas and it finally started. after warming the car up and putting it into reverse, the rpms dropped down to 600 and the car started shaking. i drove the car up to the first light, where again the rpm's started dropping very low and the car began shaking. I turned around and started driving home. i stopped at the light and again the rpms dropped down to 500-600 rpm and the car began to shake. The SES light came on. i took the car to my mechanic and told him to scan the code. the code we got was a P0300 code which is defined as a random misfire.

i decided to re-check all the spark plugs if perhaps one of them is defective. I went out to the store and bought new plugs. All the plugs seemed fine except the one that is furthest right on the driver side of the engine on the first cylinder bank ( the one closest to the bumper). the plug was all charcoal eventhough it has not even been 80 miles yet since i last installed it. From what i understand, a charcoal covered plug means it is not working. I installed new plugs and again i'm having the same issue and problem has not been resolved. the car shakes very violently at idle when in drive or reverse and lacks power at cruising speeds. i later bought a new coil thinking that it may be the problem as many here have had many fail, changed it on the cylinder that had the charcoal covered plug and again with the same result therefore ruling out the coil.

does anybody know what this can be? the problem may arise with a mistake i made while changing the plugs. when i originally changed the plugs, i didn't know that 3 of them were under the engine cover so i unscrewed what looked like a spark plug housing. when i opened it, i immediately saw that it was not a spark plug housing as it had fuel in it. i assume i unscrewed one of the injectors. i screwed it back in and it worked fine for two days. could this possibly be the route of the problem. did i damage one of the injectors or the piece that i unscrewed?

Also, i forgot to mention that when the car is running, it smells like gas. the same smell that we cross at a gas station. i assume this is from one of the cylinders not working and not igniting the fuel going into that cylinder. I tried starting the car on my driveway , and it does not start without applying any gas.

Please help guys. i want to hear some opinions before i take it into a dealer.

Thank you all.

 

Sounds like a possible leaking injector if you had removed it. It may be leaking internally or externally. Is gas pooling up in the area where you removed it?

 

change all your coilpacks...they changed the manufacturer for 99's so they are known to fail very early

 

i'm not sure if i took out the whole injector as i just lifted up the cap. the cap had a dip stick looking thing attached to it which was soaked in fuel.

i tried replacing the coil pack on the bad cylinder where the spark plug had not been working and that did not change a thing.

the injector does not look llke it has gas around the perimeter.

 

I agree with the coilpack replacement. I had a misfire a while back and replaced all 6 at 45,000 miles, sad, just sad. Also, I've always used NGK copper plugs and they are great. You change them more often but it's easy and I enjoy doing it. As far as the gas smell, if it's cranking but not starting you may be flooding the engine a little by giving it gas.

I'd replace all the coilpacks, make sure the plugs are good and in correctly, and adjust the idle from there.

Hope that helps, good luck. Oh, remember it's an 8 year old car with 100,000+ miles on it. It may need a little TLC.

 

all 6 of the ignition coils were replaced less than 30,000 miles ago

 

I'm not sure what you are talking about here. Can you take a picture of it and post it?

 

i will do so

 

I would check the coils anyway. Especially if the symptoms started right after changing the plugs. If only one cylinder is misfiring, try swapping the coil from that cylinder with one on the same bank that is not misfiring and see if the misfire problem then goes to the new cylinder. Make sure to clean up the plugs again first so you'll be able to tell which one is not firing.

 

sounds like your getting fuel. Check for spark!

At least swap 2 coils to see what happens. Then check the continuity of the harness going the the coil pack.

Pull the coil pack and plug out, have some one start the car and check for spark. works best a night.

 

coils.....replaced or not ill put my money on coils.....

 

i'll be ordering the coils from autozone. i already bought two from them. they come in Duralast boxes and say made in Japan on them. Upon looking closely at the coil, it also say's Nissan on it. I assume it's re-manufactured. But for $57 bucks a pop, can't go wrong!

 

its the FUEL INJECTORS. I replaced all this bullsh!t and left fuel injectors for the end. Idle at red light was HORRIBLE shook the car like crazy. i went through like 3 sets of sparkplugs, a set of coil packs, and finally a cleaned set of injectors fixed the problem. check out http://www.deatschwerks.com/

 

i think you can pick up a good set of used ones for about $60-80 here. all 6 of them last time i was looking around. ifs definaly a misfire and its pretty much that coil, or the harness. being back means that fuel was inject but never sparked, well its carbon but yea. fuel sprayed on the plug and your cylinder is carboned up and thats why.

 

speaking of which, I have a set of 6 used fuel injectors, that you could buy from me, send them in to get them cleaned, then when you get them back, switch them with ur current ones....

 

you did plug all the harnesses back into all coilpacks didnt you?

 

ok, yesterday, I've replaced all 6 of the coil packs. the car ran fine for a minute. A minute later idiling problems came back, and acceleration hesitation. Coil packs are no longer the cause of the problem I would think.

Could one of the fuel injectors have failed, the one I opened up by mistake? If it is the fuel injector, by simply opening up the top cap have caused it to fail?

 

Could be! You've practically replaced every other ignition component. If you messed with the injector, there was a pool of gas as mentioned earlier, and it's only on that cylinder that you have the misfire, I would start there.

 

can i change one injector or will i have to replace 3 front ones at the same time?

 

You can change just one but you will probably have to pull all 3 to install the one.

 

is it recommended to change all 3 or just the one that is causing trouble? i read on these forums that if you're changing one, you might as well change all of them. I just want to know if it's really necessary.

 

carbon fouled plug in 80 miles = seriously rich fuel mixture. 90% sure you damaged your fuel injector when you pulled it apart, it now dumps gas into the cylinder causing the fouled plug and misfiring. take it to a professional for repair (they can do just the faulty one) - you will do more damage trying to fix this yourself. and you are killing your CAT and 02 sensors in the meantime.

also, try to get your money back on all the coils you bought.

 

I took my car to a mechanic today to diagnose this problem. I will keep everyone updated on the issue.

 

ok, so it turns out the injector on the cylinder with the carbon covered spark plug was stuck open. My mechanic put in a new injector and the problem was gone. However, when I called him, he told me that the injector put in was generic. I told him that I want to buy a Nissan injector as I have a discount and can get the injector from a Nissan delaership for $80 vs. the $150 he was charging for a generic injector. So he put in my old injector and I took the car home since Nissan did not have an injector in stock for my car. The catch is that now my old injector seems to be working fine with no problems whatsoever. I will still put in a new injector just to be safe but I have to wait until Thursday for it to come in.

Also, since the previous owner used 87 octane will fuel injector cleaner help clean up some deposits on the remaining injectors? I have heard BG44k are decent. Any other recommendations or reasons against using such products?

 

I'm getting the Nissan OEM fuel filter and fuel injector in tomorrow from the delaer. I paid $10 for the Nissan fuel filter and $80 for a Nissan injector from the dealer.

My mechanic is charging me $90 total for the fuel filter install and the injector install. I've called around and know that it's a very good deal. Any opinions?

 

is it a front injector or rear?

 

it is the front injector.

the $80 includes the install of the new injector plus the diagnoses of the problem.

 

to install a front injector (1) takes literally 5 min, if that. FYI

 

Just thought I would throw my 2 cents worth in.

My fiance's 95 Maxima began running rough. After searching the archives I was almost certain the problem was going to be one of the coils. I was getting code 1320 (ignition problem) and 0304 (misfire on number 4). However, the number 4 plug was perfectly clean, and not wet. I swapped the number 4 plug and coil with number 6. But I continued to get the misfire code on number four.

I then listened to the injectors on numbers 2, 4 and 6. Number 2 and 6 were clicking normally, but no sound was coming from number 4. I then checked the resistance on the # 4 injector and found that it was infinite (should be around 12 to 14 ohms). A new injector (about $ 75) solved the problem.

The point is, don't be too quick to assume an ignition coil problem when you get a misfire code.