I went back 7 pages and can't find anything.

My wife tells me that her 1997 maxima ( mine is a 1998) hestitates and looks like it will stall at a stop sign, but it doesn't...then when she tries to accelerate, it's really slow.

I did do the throttle body cleaning last week..I actually removed the throttle body and cleaned it all up (disconnected the thottle position sensor and the four bolts..gee I hope I didn't mess with that sensor??) The only ECU code is for a knock sensor that was there before I open the hood.

Any ideas?

Thanks

 

Change the KS, its badly affects performance.

 

you should be putting premium gas in your tank... or it will mess with the knock sensor. you should replace that, its probably your problem... take care of your car, feed it like a king, its worth it because you will ruin it otherwise and have to end up paying that price down the line.

gas prices are high, but you have to think of inflation too, so its really not way off course.

 

Changing spark plugs got my acceleration up like 40 percent more, really, and I got a bad knock sensor code.

 

Are you saying the problems started after your cleaned the the TB and the TPS?

 

njmodi: My wife says that the problem was there before I cleaned the TB and touched the TPS.

The KS light has been on for over 1 month, and yes she does put the cheap gas ..(for now, I'll tell her to use the premium from now on).


The spark plugs were also just replaced a few days ago.

 

1. 1st problem - KS does not set the CEL - so you have at least one other code stored in the ECU. Pull the codes again and take not of all the problems stored (they will be displayed one after the other, and then repeat)

2. Which plugs did you use? If you used anything other then the OEM NGK platinums or NGK V-power coppers, then pull out whatever you put in and replace them with the NGKs.

 

Have the PCV valve, fuel filter and air filter been replaced at any time in the recent past?

 

having a bad knock sensor doesnt make your car stall...or feel like its going to stall.
it might vibrate, hesitate, just not pull as hard...but it shouldnt want to stall.
i had a bad one for months, i only used 94 and it ran fine. i got low end back when i put the new one in and some mpg.

 

You'll know more when you pull the codes and read ALL of the codes ...


njmodi said it perfectly.

 

this is interesting, i recently took my tb off and cleaned it, now my idle is acting funny. It starts out normal but then gradually drops to like 450 or 500, and the car starts to vibrate. I have a ks code, but there is also a crappy looking wire connected to it. So I guess i'm in the same boat. And i use 91 all the time. No hesitation, just low idle

 

The pcv will be replaced tomorrow. The air filter is very clean. Not sure about the fuel filter..I know it hasn't been touched in the last 15,000 miles (car was bought used and well maintained..with records).
As for the spark plugs: NGK BKR6E-11... but I think this problem was there before I changed them.

I did notice that on the exhaust manifold there is some heavy oil stains... I was told to replace the PCV valve, which I'm doing tomorrow AM

 

ZANDER: That could be because you need to set the TPS sensor with a mutlimeter...I remember seeing a post on how to check/change the TPS (Throttle position sensor). It has to read .5 volts, it's very simple.

 

Why don't you try pulling codes And reading them correctly?

 

http://vbxmaxima.8m.com/tps.html

Check this site out. Will tell you everything you need to know about the TPS

 

LOL...I went and check my notes..the codes as of (yesterday) were

0304 : Diagnostic Trouble Code 0304 points to a problem with the Knock Sensor.
and
0503 iagnostic Trouble Code 0503 indicates a problem with the front Oxygen Sensor

The front Oxygen Sensor was replaced a few months ago, but I don't think the ECU was ever reset..thus is why I omitted the 0503 from this discussion (thinking that it was already replaced)...but I'm not sure if after the OS was replaced the hesitation occured. After last night, all the ECU codes were reset.

 

Assuming no codes have reposted (the KS will not set the CEL - so you should check even if the light is not set), I would recommend cleaning out the IACV - this could lead to the erratic idle behavior when you are coming to a stop. The valve gets clogged over time and cleaning it really smooths out the idle speed behavior.

 

IACV? Is that PCV valve? just under the 2 long thin wires that lead to the throttle body?

Thanks I really appreciate all the help this forum has given me..

 

Check the stickies for the "how to" on cleaning/removing it.

 

..and as a bonus I also get to know about imageshack.com!! Thanks...I'll have to do this next week..

 

Have the PCV valve, fuel filter and air filter been replaced at any time in the recent past?

 

Did you plug the IACV plug in all the way? It should snap when inserted all the way. If it is loose it will produce the exact symptoms you described.

 

wow that's a monster sig.....

how is your idle under no load? it should be around 700rpm with the engine running and in neutral. maybe u just have to adjust the idle screw.

 

You referring to my post with the pic of the IACV? (Thats not a sig ), it was a picture of where the IACV was for the OP's benefit.

 

no actually it was the post above me. he had a dark 5th gen pic that took about two window widths of the browser. i remember the iacv pic. so annoying finding that 10mm bolt holding in the metal bracket. took me 20 min for just that

 

This question was posted a few back and never answered. IACV=PCV?? I'm curious because my car is falling on it's face on acceleration lately at certain random RPMs, I changed my PCV and will try to clean my EGR valve soon. Originally thought it was my new clutch that still isn't quite right, but the RPMs don't fluctuate as if it were slipping. Thought maybe coil packs as it's a 99 or Maybe KS as I have no CEL light on right now. I will get it checked out though.

 

IACV = idle air control valve
PCV valve = positive crank ventilation valve

Therefore it is safe to say PCV != IACV.

The PCV valve is located on the rear valve cover - towards the driver's side of the car.

 

No, No and Nope..but the air filter is very clean. I did notice last night that it revs at 1500 in neutral! ..when in the drive position it idles at 700-800 rpms..I didn't have time to adjust the idle. The IACV was never touched, but I'll follow njmodi suggestion to clean it..and adjust the idle, (change the KS as a last resort), change the PCV value..gosh so much work...

 

not trying to sound like a noob, but I need some help with the multimeter. I pulled the tps off the throttle body, and now its a little off track. I can tell because somtimes the tranny shifts too early and the acceleration isn't the same as before I removed it. I hav a multimeter from harbor freight. I just need to kno wat setting do I put it on to test the tps sensor? as well as coils ect. it has 3 holes. where do I put the red and black wires?

 

If after cleaning the IACV, TB, & changing spark plugs (which sounds like you did), make sure your coils are all good, and if that doesnt work, then the fuel injectors are next...I had a real bad idle and checked/cleaned/replaced everything intake/spark related and it ended up being one of the front three fuel injectors. The crown was completely gone. The car idles perfect now, the needle doesn't even move at about 550rpm in gear, and 700rpm in N. The exhaust sounds cleaner and healthier so it definitely made a huge difference. MPG increased as well. I just grabbed some injectors off a low mileage max at the junk yard and was good to go. Got all six oem coils as well for $10, versus $78 a piece at AutoZone....lol. Good luck!