Hello,

I have a 91 Max SE with 143K on it.
I have recently noticed that the engine is idling roughly and running roughly (though not as noticeable as idling). The rpm at idling is steady, but that's probably electronically controlled. I had a fuel injection cleaning done at the dealer last week with no improvement. I changed the spark plugs too. The distubuter cap, rotor and plug wires are 50 k old.
Any idea what the problem might be?

Thanks.


91 Maxima SE 5-Spd No modifications.

 

The throttle body and intake manifold is full of carbon that restricts and disrupts the air flow. The build up is due to the oil vapor coming from the PCV system and the hot exhaust gas from the EGR. (The older, and more worn the engine, the bigger the problem.) Since the incoming fuel, from the injectors is way downstream none of the curd gets washed off, and so it builds up. Injector cleaner and a soft brush can remove quite a bit of the build up (particularly the throttle body), but won't get it all. Some shops have a setup to "fog" the intake with a strong solvent that will get more. You can also remove the top of the plenum and scrub it yourself.
Also check for hard/leaky vacum lines.

 

I thought they did the throttle body along with the injectors. I will have to call and check.
I also noticed a drop in gas mileage.

 

Like brubenstein suggested... check your PCV valve, I just changed mine this weekend... easy... also I've had an ijector replaced before, make sure the fuel is geeting to the engine smoothly first before you consider the injector (not cheap...) check the fuel filter as well. Your gas milage problem might also be related to your O2 sensor... @ $120... good luck.

 

The car vibrates pretty rough when idling at a stop light in drive... I also only get about 210 miles per tank now. Recently I hear this constant clicking noise as I accelerate...thats the most annoying. I just don't know what to do with this car!?!?!

PJ

 

[QUOTE]Originally posted by speednsound007
[B]The car vibrates pretty rough when idling at a stop light in drive... I also only get about 210 miles per tank now. Recently I hear this constant clicking noise as I accelerate...thats the most annoying. I just don't know what to do with this car!?!?!

When was your last oil change? Did you use a factory filter?

 

Dude, I've got the same problem with my 91 SE. I specifically feel the vibration on the steering wheel and only when in "Drive" at a stop light.

So far, I have done the following replacements:

New NGK plugs, Purolator fuel filter and pcv valve, air filter------did not help the vibration.

I also recently changed my oil and put in a Purolator oil filter, with no change in the vibration.

I am really getting nuts without any solution to this problem.

 

Did you change your plug wires? That may help too...

 

I had what I thought was an idle problem but it turned out that 2 of my engine mounts were shagged.

If you have tried everything else, have these looked at.

Brent

 

From what I hear rough idle (especially when at a stop light) is very common with the VG's

 

Well I took the car to the dealer.
They looked at it and said they could not feel a thing.
Either I'm too picky or they don't know much.
In any case, I'm not going to worry about it since the car is running. Period.
I found out that unless the car is really acting up, not just imperfect according to me, there is no sense in taking it to the dealer.

Thanks everyone for the input.

 

Ive mentioned on some other posts that i had a similar problems on my 91 SE, i did a complete tune-up and it still was doing it , even worse then before when i would start it up, well waht had happened was my injector ends had gotten corroded and were not conducting electricity to the injectors like they should,i went and bought 6 new injector ends and replaced them, i also sand blasted the connection point on the injector to get rid of any excess corrosion, seemed to fix my problem................

 

Check your ignition coil. You should measure just a couple of ohms on the primary, and 10k ohms on the secondary. I had the same types of problems that I am reading in this thread, and what I found was my secondary measured 10M ohms!!! And get this: the coil-to-distributor wire was open!! The only way this thing was running was the arching that had to be occuring in the wire (Not to mention the bad coil).

Jamie

 

Hmm... This is weird. I have a smooth idle in D, but it's rough in P or N (no load). Car runs fine otherwise. Consistent 27-28 MPG combined city/hwy.

 

I kinda agree with you. I have taken my car to my mechanic two times regarding the rough idle, and every time he tells me that there is nothing wrong.

Maybe I am too picky or just obsessing too much about perfection.

 

It kinda makes sense, but as soon as I raise my RPM the vibration gets lessened.

But I will definately have the mounts looked at during my next appointment.

 

Since the injector ends seem to present a problem, I'm going to look at them.
Are they easy to get to? How much dis-assembly does this job require?

 

5 of them are not that bad to get to but one of them requires the manifold to be taken off if in not mistaken........