Okay so here's the deal-

My engine is shuddering while at low rpms, and I'm not sure why. Once it gets revved up a bit (above 1500 or so) the problem seems to go away, but theres an obvious power loss. I have already changed the spark plugs, checked oil, done fuel injector cleaner and stuff, but nothing has worked yet. Any ideas? I'm thinkin it might have something to do with the fuel injectors but im not too sure. Thanks

 

prolly your coil packs, brah...

 

Does it feel like a misfire or does it feel like the whole engine itself is moving? Mine has a shudder in the lower rpms also and I think it may be the motor mounts. My front end shakes in the lower rpms.

 

mine shutters when I hit the gas only 1/4 throttle but very quickly between 1500-2000 rpm's, it's def. a misfire and it's caused by my egr even though it's not throwing any egr codes anymore, that was like the final straw for me, w/175k on the clock I figured it was just as easy to pull the motor as it was to remove the egr.

 

Has the check engine light come on?
How long have you been experiencing this problem?
What plugs did you use, did you gap correctly?

* Could be your Ignition coils, Bad MAF, faulty EGR valve, clogged fuel filter.

 

Also, read the 4th gen sticky to check your codes yourself, even if the CEL isn't on, knock sensors on are cars melt and break like a trojan ultra-thin, and they also cause "an obvious power loss" but they only throw a 'ghost code' i.e. no check engine light.

 

I'd check the knock sensor, When I started getting a shutter, the cel went on for the knock sensor.

 

To answer questions:

I think it feels like a misfire, although when i check under the hood while running there is some vibration of the motor...

Also, when I did the plugs, it said that the gaps didnt need to be set, and my car worked for about a month after replacing the plugs, so I dont think that would be it.

The CEL hasn't come on, but I have a feeling that it may have been pulled at an auto-repair place, cause I have yet to see it.

I'll check KS & ignition coils... thanks and I'll let you know what I find.

 

I don't think it's u'r knocksensor, a bad KS doesn't cause the symptoms u describe.

What kinda spark plugs did u use?

To check to see if u'r CEL bulb is working/installed just turn the key and all the lights should light up. The CEL is the farthest light to the right.

 

The spark plugs I used were Bosch Platinums. It said that there was no need to gap them. Also, I noticed the problem before I installed the plugs, and then it went away for a little bit, and now its back again. I'm thinking it is something other than the plugs... but who knows

 

What type of plugs were in it before? I've read about people having problems with bosch platinums on our cars. Especially the +4's. They also caused a CEL for some people. I tried running autolites in my car and it ran like crap. It misfired like crazy even after I gapped them. I threw in some NGK iridiums and it ran much better and smoother. From now on I only go with NGK.

 

I would definately put back the OEM NGK Plats in. When changing the plugs inspect each one of them to see if there is unburnt gasoline on them. This will be a sign that there is no ignition in that cylinder. If this doesn't fix the shutter I'm pretty sure it will narrow it down to MAF or Coils.

 

I'm beginning to think its coils, cause this shudder happened once even before i changed the plugs. I'll check the plugs, but how much do coils usually run? Are they easy to change?

 

www.pinnaclenissan.com they'll run around $426.00 for the six pack. That's OEM, I don't know what your aftermarkets will run you. Some peope on the org. have bought them from their local parts store for a lot cheaper. When it comes to components like this I don't mess around w/ cheap aftermarket crap. I'd stick with OEM.

 

eMart8 - Do you get stuttering when you accelerate? If so, it's most likely your coils. If it is your coils, they should throw a 060X (where X references a cylinder). I wouldn't replace them until they do - in the mean time, go into the 4th gen parts for sale and buy a set of used coil packs for around $70-100. Coils are SUPPOSE to last the life of the engine.

Have you run injector cleaner through your engine? Changed your fuel filter? Replaced your PCV valve recently? IAC valve? Clean air filter? Cleaned off your MAF sensor mesh?

Check your vaccume hoses too.

 

Finally got it figured out. It was a cylinder 3 misfire, and when the fuel injector got moved from 3 to 2, it changed to cylinder 2 misfire.... so, obviously that fuel injector. Part cost about $130 or $140, and shes runnin fine now. Thanks everyone, i appreciate the help. Should I expect the other injectors to go out soon too, or should this just be a one time thing? Those things should last the life of the engine right?

 

don't even bother changing the injector...it's a rare problem. But then again...you'd know what to look for if this problem recurs on other cyclinders. I'm just saying don't waste money.

 

I purchased a used injector from Jsutter for $10 each... for the future...

 

I was throwing a 0302 code so I cleaned my TB, IACV (including the sensor inside of it), MAF, EGR and EGR tube with all new gaskets. The coolant temperate sensor was also replaced. The knock sensor is only a few months old. No codes have been on since I reset it.

My erratic idle went away along with the low speed stalling. Throttle response seems to be much improved and car seems smoother and more powerful overall.

But after driving it a day or two I noticed a shudder while driving a perfectly smooth street. It only does it when I doing about 30-40 mph rpm's are around 2 to 3 K. It doesn't do it while the car is going faster only slower with the gas pedal very slightly pressed doing about 30-40 mph. keeping it steady.

I've scoured through the forums but still am unsure what it might be. It wasn't there before I cleaned everything. Could I have messed up my MAF while cleaning it. I was very careful and only used MAF cleaner or could it be a TPS (throttle position sensor)?

Thanks for any help.

 

knock sensor will not throw a code, its a ghost...

 

autozone free scan dude, dont pay for a scan

 

I replace my knock sensor 3 months ago with an EOM Nissan knock sensor. You said knock sensors won't throw a code. Is P0325 the knock sensor code?

 

P0325 is the code for a KS with a reader. 0304 is the code if you read the flashing lights when you get the codes with your CEL (twist the screw...count the flashes slow first, then fast...twist the screw again to reset)