I decided to change my sparkplugs NGK's on my 98 Maxima for some reason 1 week later rpms start going up and down when the car is at idle just alittle bit up then down and car shakes like its a misfire but not a misfire..

I told my mechanic he says it might be the Gas try putting 89 in there I usually use 91. I put 89 in there drove for 30 miles problem is still there.

He says it could also be my air flow valve sensor. While looking at this problem I found out my throw out bearing is also going bad a clucking noise started coming out from that side when the car was shaking.

Is it really the sensor causing the shake to come and go? or is it a fuel injector or something? Because I did not have any problems with old spark plugs..

 

your mechanic told you to put 89 in there??????

 

how was it right after you changed the plugs? ohh and it looks like its time to find a different mechanic.

 

He says there is something in the new Gas that might be giving me the problem, It actually helped for like 6 min the car had no problem with idle then started jumping again..

Could it be the air sensor valve or not? Anyone ever have this problem before when the car shakes alittle at idle? not the big shake when u lose a cylinder.. some minor choking of the exhaust aswell.

It was wierd my CEL always stays on because I have an Auto to manual conversion, I drove the car for 70+ miles parked it had no problems then started it up CEL was gone and car was shaking at idle 30min later on the highway the CEL comes back on but the shaking didnt go away.

 

When we were changing the plugs the rubber peice on one of the back fuel injectors ripped off, He had a spare brand new nissan injector laying around but it was for the front we tried it but the car shaked alittle just like it is now but alittle more, so we took it back out took the rubber peice off put it on the old injector put it in and it worked fine. I drove for exactly 7 days 400+ miles with no problems.. Any ideas?

I am thinking it is that fuel injector that went bad or is it the air flow valve?

 

did you swap your auto ECU for a Manual ECU? If your still on the auto ecu then you might get funny idle and a ton of check engine lights

 

What brand/model of new plugs did u install?

 

First off, find another mechanic to work on your car.

You probably have a COIL PACK thats not seated on a plug correctly or just not getting a clean signal from the ECU to fire. Try disconnecting and reconnecting the coil packs, making sure the connections are clean and tight. You can spray some WD-40 right onto the electriacal connectors to make sure there clean, moisture free and tight.

 

Surely you didn't mess with the fuel injectors when changing your plugs.

What kind of plugs did you install? Certain plugs don't work well with distributerless ignition systems.

 

Did you gap the plugs correctly? Gap should be .044" Use NGK Copper plugs if you don't want to pay for the NGK Platinums.

Redo the plugs (just take them out and regap them and put them back in). Make sure you connect the coil packs back properly.

The MAF (mass air flow) sensor would cause your idle to go crazy, but I don't think it makes your car shake. It could be the plugs or a coil pack that's about to die causing your car to shake If you still have your old plugs, put them back in and see if it makes a difference. If not then just buy some coppers ($1.50-$2.00 each) and gap them correctly and put them in.

Since you're in NY, I'm sure someone local to you (ask in the Regional section) will let you swap out the MAF sensor for a minute...

 

NGK Platinums.

 

I have been driving like this for 1 year with no problems. I called Jeff @ Maximumtunning I will go by there tomorrow and let you guys know.

 

I just started her up, shaking is almost gone.. I am really confused why would it work for 7 days with no problems then start acting up? Wouldnt it act up right away? anyone have any ideas...

 

Ok. From reading all the threads I am NINETY percents positive it is one of your ignition coil.

I have had this problem before when the ignition coil went bad on one of the cylinders and my car would shake a little bit while idle (at the red light for example). It doesn's shake wile moving though.

Inspect all your ignition coils, replace any bad ones, change the mechanic and don't change octane rating (use 91), alhtough I use 89 for now due to high prices in California.

Good Luck out there.

 

How do you inspect them? I also think it was that and I even know the one that I think is bad too because that was the one the rubber peice ripped on.

 

WELL of course it can be one of the coils. Well, to tell you the truth I have had 2 bad coils. I've bought one (not to dissaponit you it costs 90 bucks in autoparts store and dealer sells it for around 200). The other was almost bad but I kinda played with it, fixed the spring inside and it works fine (just had my sparks replaced).

well, see if you can put the bad one again and finally if it doesn't work, replace it and also replace the mechanic :-) Just kidding.

 

I saw the spring fall out when we were installing it then he just put it in and installed it.

I will replace that if it does not fix the problem, I will check the air flow valve..

 

well then it is 150% your ignition coil. There is a tread here on the forum where about 30 people have the same problem where on or two coils have already been replaced. Welcome to the team!

 

How much do they usually cost? Is there anyway to test each one?

 

it costs about 90 bucks in autoparts store and dealer sells it for around 200
Maybe a mechanic shop will test. But if a spring has fallen out, you ll prob have to change it.

 

You can buy used ones in the Classified section of the forum or check eBay. You can buy new ones from online dealerships that give discounts (http://forums.maxima.org/showthread.php?t=305931 or you can try Jerry Rome's Nissan)

 

I will just get it at the dealer, I have the 20% discount. What is the exact name of the back row middle one? Or are all 3 back ones the same? I know the front and back are different.

 

I think they are the same, but I can be wrong! it is either 1st or 3d or 5th cylinder

Let the dealer know that it is a back row.

 

The front 3 (Bank 2) are the same and the rear 3 (Bank 1) are the same

 

My check engine light is always on because I have an automatic tranny ecu in there and have a 5 speed.

When we checked the codes it just gave 0505 wouldnt it give a misfire code or a code for ignition coils or is there no code for ignition coils?

 

Coil pack completely dead = CEL
Coil pack dying = no CEL

 

OK, thanks everyone! I will give it a shot tomorrow will buy a coil and hope everything is fixed.

Should I also change my air flow valve sensor? At every red light when the car idles rpms stay over 1k then drop is this sensor bad or is it something else?

 

When one of mine had to be replaced, I got it from a dealer for about $85. This was little over a year ago.

No way they could have gone up to $200 that fast.

You can get them from www.jerryromenissan.com for $61-66 each depending on which one you need.

Just go to their parts section and search for "Ignition Coil" under the Collision tab.

 

I didnt change my Coil, I bought a new Idle Valve Air Control Sensor; That seemed to fix the shaking at idle the rpm goes up and down sometimes but not as much as it used to.

I also ended up changing my clutch, Anyone ever burn an ACT clutch in 12k miles? I beat on it all the time it was well worth it