When the car is cold, it tends to buck or surge at low speed. When the car is warm, no problems at all. I've had the mass air flow sensor replaced in august. I've read over the faq, can't quite find the solution. Is it the coil's or mabye fuel injectors? The car has 91k miles, I'm the only owner. No service light is on...

Any help/direction is appreciated.

Jeff

 

that happens to me too
i only drive the car on weekends...so im just assuming its the car's way of warming up after a decently long period of sitting.
i only have 22K miles though, should i be worried too?

 

My '01 has done this a few times, always when I try to add what must be just a tad too much throttle too soon, so I just go extra-easy on it for the first two minutes.

Problem solved plus I know I'm contributing to the longevity of the engine even more than usual/normal

 

this used to happen to me then i replaced my coils but my check engine light came on after bout 2 weeks of this if it turns out to be the coils i can get em to your door for 250 shipped but i wouldnt replace em till ur sure thats the prob

 

Thanks guys. Question for you twllin, are the coils burried or are they somewhere reachable. Hard job to do or farily simple.

Thanks
Jeff

 

I'll answer that: If you know what you're doing the coils can be changed in 30 min. If you don't know what you're doing it will still be under an hour. They are easy to do and WAY cheaper than paying a dealer.

I have a 00 SE and this exact problem. For the few min prior to warming up the thing bucks/surges like nothing else. Once it warms up and the needle gets above C I'm good to go. I've got new spark plugs on there and new coils. I was told coils may be the problem (they were fixing nasty spark knock anyway), but they did not fix this. I just ran some BG44k through. Problem persists.

I have a 5 speed and have found that as long as I keep the RPM no lower than high teens, preferably around 2k or so until it's warmed up, then the bucking is not there. So, as I run up my street I set it in second or third at no less than 2k and once it's warmed up I'm good to go.

I posted this problem elsewhere and was told it could be bad plugs, coils, dirty injectors, bad coolant temperature sensor, bad maf, or bad atmospheric temp sensor.

It is clearly not plugs/coils in my case. Dirty injectors doubtful since it's still there just as much as before the bg44k. Bad coolant temp sensor absolutely not, because the car idles high around 1500 while cold (as it should until it warms up).

Bad atmospheric temp and maf it just doesn't seem to me like those could be the cause, and since you replaced the maf the problem persists it's probably not the cause.

Basically this is because caused by our engines running lean. A cold engine needs a high ratio of gas to air. Instead of the normal 14:1 or so (I think that's it) a cold engine needs 10:1 or even much less. So, we have either a lean mixture, or misfires when cold (hence the recommendation of coils fixing it). In my case it wasn't coils or plugs, so I'm sure it's lean. I just don't know WHY the thing is running lean. I recently unplugged the battery for a few hours to reset the comp and the problem is still there.

I'd love to hear any ideas

 

I have these exact same symptoms usually (I rarely notice them because I rarely take it above 2K-3K RPM when it's dead cold...)
I've never changed my plugs, MAF, coils, etc. (yet)
I do understand that Cali-spec engines have the Swirl control valve, which is active below 3600RPM or so, when the engine temperature is between something like 45 or 50F and 120F... this chokes off the intake runners a little, for emissions reasons (adds swirl to the air coming in). Maybe when it's cold and above 3600RPM it runs leaner?

 

they hit it right on the head and yea the coils are very easy to change you know wher eu plug in your spark plugs right? Well u know that boot type thing that you put in the hole on top of the spark plug? thats the ignition coil. Theres 1 screw per coil and one clip per coil its easier then changing your spark plugs truse me save urself hundreds

 

hey guys, i've had the same problem in my 5 speed max. Changing out my exhaust w/a y-pipe and a catback helped a little, i guess more room to breath. But the biggest thing that i did to help was to clean out my throttle body. Made a world of difference. I just did this a couple of days ago and i was amazed at how much smother the car ran. jclemen, my car only has 53k on it and the throttle was dirty as he11. I would high recomend doing this before spending alot of money on coils. Takes 5 minutes and costs about $3.

 

How'd you clean your tbody in 5 minutes?! It took me at least a half hour of playing with screws and crap (one of which is still somewhere in the engine bay hehe) when I cleaned mine. BTW it didn't seem to fix my problem.

My vehicle is federal emissions also.

 

How about Vacumme leak.

 

Would that manifest itself in surging only when the car is super cold and if so, how?

 

SkoorbMax had suggested the surging was tied to running lean. A vacumme leak after the AFM would have the car running lean during open loop mode.

 

My Max does the same thing when really really cold. It gets kinda like hyper sensitive to throttle input. I've already replaced the plugs, coils are fine, MAF also fine. Once again I think it is just another one of those little quirks that our cars are known for haha....

 

Great info. I had new plugs and the maf done in august. I brought it in for its 3rd o2 sensor and had the combustion chamber/throttle body cleaning done. The symptoms everyone is describing is exactly what I'm experiencing. If you keep the revs up, no problems. My problem is, no service light yet so its hard to pinpoint the problem. With 91k on the clock (5speed), Im thinking its fuel injectors or coils. ????

Jeff

 

haha... it really took about 10-15 minutes but was really easy b/c I have a Place Racing cold air intake. It's really easy to get to the throttle body. In my case, I think that the intake, exhaust (y-pipe, high flow cat, catback), cleaning of the throttle body and using a fuel system cleaner all helped to eliminate this problem. I used to have this same problem and it drove me nuts. I didn't get these mods to eliminate this problem. But the combination of them did get rid of it.

 

I have same symptoms as well on my 2k 5 speed CA emissions w/supercharger. Sc seems to magnify the problem. The SC was installed when the car was brand new and I have been battling this ever since. Mine doesn't go away after warming up though. My guess is it is fuel mapping related and will require new ECU programming. I don't think Nissan will fix it based on the cold emission levels on the car changing too much.