Ok have been having a long battle with a 2000 maxima with 176000 miles about. Problem is a misfire that makes the car buck and seem to want to stall out. Have done the following. Cleaned throttle bottle and iacv. Rplace maf..coils...plugs..then realised gas tank had a nipple rusted off and the fuel filler neck was rusted. I replaced both from a local junkyard. Got the check engine light off and car seemed to be running well. But as usual ran great for about two days..mostly around town under 50mph. ...then right back to original problem. This time however I get a code for the coolant temp sensor and switch. Anyone had a coolant temp sensor and switch cause the same problem? Only thing else I can think of is intake manifold gasket.

 

Also have replaced the fuel filter and the fuel pump. In fact that was the first thing I did.

 

Anyone tell me where this should plug in?

The hose im holding..looks like it should plug into air box but no male connector anywhere.
Starts right behind under starter

 

I'll save child the grief: Looks like a tranny vent, dude. Check for vacuum leaks/unmeasured air leaks and pull your codes. Not sure about the VQ30 temp sensors and switches and stuff but does not sound like the two (surging and ECTS) are related. Let us know how it goes.

 

Yeah thanks man. I'm an idiot. Not used to working on front wheel drive cars. Honestly this car makes me wish I had kept my jeep. Bought it during the winter and wasnt under it enough to see half the rust underneath. Ran great all winter except for no interior lights no defrost on rear window and i cant unlock the doors automatically. P0115 was the code I got when it happened this time. I was told to replace the sender and sensor so 21 bucks later I placed my online order. So I'm getting alot of magnets on my fridge and hope to avoid any more. If I spray some carb cleaner around the intake would that be able to tell me if I have leaks like doing the same thing with a headgasket? I watched the video for upper and lower looks like a pita..would like to try to rule that out.

 

After 2 mos of throwing parts at my 2000 maxima I finally got a code for something . coolant circuit. Replaced the temp sender and sensor...no rough idle. No misfire. Took it for a decent drive and I admit it seems to have alot more pep. I don't want to get my hopes up yet but I replaced or ruled out everything else but the injectors due to the fact that I dont have any o rings and I dont want my engine catching on fire. I'll keep you updated. Never knew the temp circuit had sh*% to do with the injectors. Thanks to all that threw me info.

 

Noooooooooooooooo

I could see some odd case where it puts it into safe mode and runs very low ignition timing. I don't think it should cause it to run bad, though, so that's weird.

 

Alot of stuff on the net about it actually ...it does control the amount of fuel the injectors get. But like I said....not getting my hopes up.

 

If it read cold, yeah, it would enrichen, but that still wouldn't cause issues, it would just be in the 12s:1

 

I'm not a mechanic. Obviously..lol or I wouldn't be throwing parts at a 19 yr old car. I have honestly spent more time changing parts on my max than driving it in the past two months. The mechanics that I do know have told me over and over that it was spark causing my problem. I tried to get it in to a local shop for a diagnostic and was basically told how busy they were and the guy told me some things to look for to try to diagnose it myself. I admit I didn't use hitachi coils...didnt use ngk plugs..used the best champion plugs I could get..used a brand of packs I have never heard of because I couldn't afford to keep dropping over 200 dollars every time it acts up. I'm not saying you are wrong ...I'm hopeful you are wrong..but this car literally runs great every time I work on it only to go right back to the same situation..usually within two days. I have looked alot of the symptoms up ...been on 3 different forums for maximas...it's been exhausting. But on an audi forum , I found someone with the same exact issue..they replaced all the same things ..did all the same work ..had the final same code..and 8 bucks later they solved their problem with a coolant sensor. I'm far from electrical savvy..so I just keep going through the codes I get and from the experience I've had from other cars have tried to apply that to my max. However I promise you if you do a simple google search can a temp sensor cause a misfire you can easily find all the information about all the same symptoms of a bad coil pack..plugs...intake manifold..bad fuel injector..etc etc

 

Never mind the intake manifold gasket. Stop speculating and listen to your car. The Coolant Temperature Sensor is only a few dollars, here: https://www.rockauto.com/en/catalog/...+/+sensor,4748

 

Installed it today. Drives great. No misfire. No rough idle. But that's why I kept throwing parts at it . I give it two days before I think I get it beat . Usually it only takes two before it goes right back to the same symptoms. But I took it on the highway and really opened it up and had no problems. No sevice engine.. This car really makes me want to invest in a diagnostic tool ..OBD?

 

The car is running great. No misfire ...no bucking ...no loss of power. I did of course get another service engine light. 2 codes one 1448 the other one I dont remember off the top of my head but both deal with the carbon canister for emissions. Pretty expensive so might be heading to the junkyard. Already tried swapping my gas cap from the old fuel filler neck. Doubt I'll get that lucky but hell never hurts to try. Pretty sure its gonna end up being the valve. At this point Im just happy to be driving it again.

 

Vent valve

 

Why didn't warm it up by running the engine and measure it's resistance? As well as check to make sure it was receiving a 5 volt signal? The tell-tale sign usually is hard to start when really cold and once it warms up it runs like a POS and drinks gas like a AA senior member! In open loop it's not obvious unless it's extremely cold! In closed loop it's usually running extremely rich idle sucks, bogging, poor acceleration, por gas mileage....