02 nissan shaking at the start

I’ve got an 02 nissan with 70,000 miles.



So a few months ago my car will at times shake for 10-30 seconds right when i start my car in the morning—or after work. In neutral, it will rev up to about 2, or fluctuate for a few seconds. If it’s pretty bad, and it will make the check engine light go on.



the first light—they told me to replace a spark plug and coil—the second light, they told me to replace the other three as they were all obviously failing. the THIRD light (400 miles later) they are calling a “missfire” and don’t know what’s up. the shaking happens more often now.



it drives perfectly fine after the shaking stops and revs go back to a normal level.



any clues what’s causing this?

Starting to think the copy and paste of Joseph e is a good idea, So what maintenance has been performed on your car?

Did nobody ever bother to replace the spark plug wires when the plugs were done?

DID you replace those spark plugs, as advised?
“In neutral, it will rev up to about 2, or fluctuate for a few seconds”. What does this mean? Is that 2 a 2,000 rpm? What fluctuates a few seconds? Does the engine idle, actually, fluctuate; or, is it just rpm gauge indication? What misfire code(s) are scanned?

“Any clues?” WE have very few clues, from you.

Sorry—first time having car issues, I’ll be more specific. This is a 4 cylinder automatic nissan with 70,000 miles on it. Two years ago (at around 50,000) I replaced the air intake valve. When that broke down, it was a loud popping and the rpms began fluctuating widly and my car became undriveable. No problems since then until now.

In January, I started replacing all my fluids—did transmission, brake, and collant. At the same time, the car was ‘jumping’ slightly when it was idling–brief shakes that would happen every now and then. I took it to the dealer and while there wasn’t an light to check, they did notice my spark plugs were very worn down, so I replaced all four.

Starting after that, every now and then (maybe once a week) the car would shake when i start it. The shaking could best be described as when I start the car, the RPM gague JUMPs RAPIDLY up to around 2,000, and I can hear the engine is working much harder than it usually does–it’s louder, and at times the RPM needle will move around a bit from the 2000—The mechanics have been unable to replicate the shaking because it usually has to sit for at least 8 hours first—but once, when i picked up my car, the mechanic had the hood up when i started the car and he noticed the actual engine is shaking in its place when it happens.

The first check engine light came on—again the car drives FINE after this weird starting–and after maybe two days I take it into the shop. Apparently after i dropped it off, the light went off because they called to tell me no codes were registered and it appears the light never came on. i felt a little crazy.

It kept happening and after a really bad one (maybe lasting 30 seconds) the check engine light came on again and I took it in. The code read a convector coil and spark plug were malfunctioning, so I had both replaced.

The shaking never stopped, and a month later, again after a bad start, the light came on and it was the same code, for a different cylinder. I had them replace the plugs and coils for the remaining three cylinders because I didn’t want to have to keep coming back month after month for the same problem.

Since then, I drive it very rarely (10-15 miles a day?)–the shaking continues. Some times (maybe 4 total) when i drive home in rush hour after work (30 minutes on back roads) I can smell a burning smell and once I’m home–the engine is emitting a very slight odor of burning, or something–it’s very slight, i have to put my nose to the hood to smell it.

No clue what misfire codes were scanned—sorry, they just said it was a missfire and no codes were produced.

again—that’s all i can remember. not a car person, sorry if the vocabulary is all wrong. just want to have my car fixed.