I took out the EGR valve while the car was running and it caused a problem, so I am guessing it is working correctly. I checked the EGR tube and I can't find any clogs.

 

The EGR is a tube about 8in long that connects to the back of the upper intake manifold. You took it off and left the spot it connects to just open? The EGR has a sensor on it so if you take it off, it will send a code. Anyways, if its not clogged then it should be good. Next step, have you cleaned your IACV? if so how old is it? and pull all of the coil clips(the grey connectors) off and check they are good. Again, if the idle gets worse after you disconnect it then the coil is good but if nothing happens then they are bad.

 

The EGR was fine in all respects, but I did decide to go ahead and change my spark plugs even though the dealership "said" they had just done a tune up. They obviously lied..........the plugs were fouled and some of them were purple where the spark gap is. I changed them for NGK Double platinum. I did notice that my idling throttle increased by 200 rpm after the change. It was at around 700-750 rpm and now it is sitting on 950-1000 rpm. Is that too high or is that normal?

 

EGR is fine. I did not see any clogs in any of the connected hoses and the valve is not showing any errors on the computer. I am really getting aggravated with this problem. The thing that I don't understand is the inconsistency in symptoms and the fact that I have not gotten a check engine light.

 

Without turning your car on just the dash lights make sure the check engine icon lights up ,sometimes the bulb can go other times a shady seller removes it ,again check your grounds by the battery and on the intake,look up big 3 upgrade almost always a change for the better my 0.02 cents .....good luck

 

you didn't mention you cleaned the EGR tube...you just said it doesn't throw codes on the computer. Did you actually clean out the gunk like was suggested to you back in post 40, and 42? Again, the TUBE, nothing you can "see through" (not hoses, not the valve itself)...the TUBE gets cleaned. Do that.

You messed with the idle back in post 32 (you say you did anyhow), then when you changed the plugs I bet you didn't change the idle BACK to where it was originally, which is why you are idling high when your car is warm. Warm idle is 750 or so, not the 1K you say you have.

 

I posted the idle specs somewhere in this forum, and I know other people besides me have posted it too, 750rpm IIRC is on the high side of things, 900-1000 is just too high.

Honestly it's a 5mt it should be like 500-600rpm idle.

 

I fixed the problem. The fuel pressure regulator was clogged. I cleaned it and the ERG valve with some carb cleaner and the car runs perfectly now. I feel like an idiot because the first time I checked the "erg valve" I was really checking the erg vacuum solenoid and diaphram. I guess it wouldn't make a difference becaues the solenoid only operates at like 2000 rpm not during idle. It was a pain to take out the ERG valve though. I had to take apart the throttle body, disconnect a lot of hoses and remember where to put them back. Idle stays around 500 to 600 rpm and there has been no instance of hesitation or stalling since yesterday. I guess the computer told me the O2 sensor was bad because the fuel to air ratio was being altered by the Erg valve and the fuel pressure was getting messed up. Both were clogged, but I don't think they need to be replaced.

 

Good job, glad you found the fix, and guys, havent any of you thought that if OP claims this to be an se-l, for one they should post pics of exterior and interior,and also that maybe late in 98 they introduced the se-l for 99 but carfax vincheck etc etc call it a 98 due to manufacture date? ive seen it before, not like it matter....why not ask the color of the car there are certain color codes not made from year to year..with all this mumbo jumbo being said id like to see pictures of the car myself seeing as i own a 99 se-l

 

Nice....good choice on getting the maxima,without spending a dime!!!!

 

Op to eliminate coil packs as your possible problem get electric tape and wrap all cp's from the button up to the base of the shank. If the car runs fine after then you have c.p problem.

 

I would definitely check the coils. Also since you mentioned when your doing 60 it starts hesitating on you unless you full throttle, I would also check everything fuel related (i.e. fuel pressure regulator, fuel filter, fuel pump) just to be on the safe side. Gauge it if you can.

(Didn't realize you already figured out it was the regulator until after my post lol)

 

bro check the dates on these threads. This is from 3 years ago and the issue was resolved anyway.