# 98 Nissan Frontier Missing Very bad



## jchjr1122 (Apr 9, 2005)

Hello all.
I have a 1998 Nissan Frontier 4 cyl 2 wheel drive. The problem is that it is missing. I can feel it slightly when it is in park but it gets extremely bad when it is in gear. I have changed the spark plugs, wires, dist. cap, fuel filter and the module. The people at autzone said that they could not read the code that pulled up I would have to take it in to a Nissan shop to figure what it was. The check engine light is on and has been on for a while. The weirdest thing about this is it does not do it all the time. 
Is there anything else I can do besides taking it in.


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## Tonyo44 (May 9, 2005)

*98 frontier missing*

Could be the knock sensor. If it runs right when its dry but misses when its damp or raining its a good chance thats it. You could also check it out by waiting until its running right. Then when the engine is cool hose down the intake manifold with water and see if it starts missing ( the sensor is located under the intake manifold about center I think). If it does its probably the knock sensor. Nissan wants about $300 to replace it but I've seen them for about $130 on line.


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## Warhorse46 (May 11, 2005)

:fluffy:


Tonyo44 said:


> Could be the knock sensor. If it runs right when its dry but misses when its damp or raining its a good chance thats it. You could also check it out by waiting until its running right. Then when the engine is cool hose down the intake manifold with water and see if it starts missing ( the sensor is located under the intake manifold about center I think). If it does its probably the knock sensor. Nissan wants about $300 to replace it but I've seen them for about $130 on line.


 :fluffy: 

Lambs to the slaughter... Sorry guys but having first hand knowledge of the good ol knock sensor I can tell you most certainly if you replace that piece it will not fix your missing unless it is showing in the computer as the only bad part. The knock sensor is only a detection device a microphone if you will on the engine. What codes are coming up in the computer? Have you had it checked on a computer at least a small sun diagnostic unit. Is the check engine Light on? Has the EGR valve been replaced and how many miles are on this truck? I have read through out these forums of dealers pushing knock sensors as a fix but believe me I have a 98 4x4 with the knock sensor hanginging cable tied to the battery, the knock sensor is not the issue here. Mine has not given me one small problem since I replaced the EGR valve Seafoamed the engine and replaced the knock sensor but have since put the original one back on and tied it out of the way. Also a carbon build up in the intake manifold for which you'd use the Seafoam is a major reason for missing.

Talk at you later Warhorse46 98 4x4 XE std


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## Tonyo44 (May 9, 2005)

*Lets see*

Ok, I'm open for suggestions. Lets back up, mine is a 98 frontier with 190k thats barely been touched. I see the point about the knock sensor. All mine is is a coil or choke. Or at least thats what it looks like. Turns out I took it to the dealer and he had it all day and even took it in the shop but did nothing. Who knows? They did put it on a diagnostic device and supposedly it let them know through a history of codes that the knock sensor was bad. That being said, I picked up a cap, rotor, wires and set of plugs. I'll put those on and we'll see. Just what is Seafoam and where do I get it. I'll also check into a EGR valve, shouldn't be too much. If anyone has any info on how a knock sensor works I'd like to see that also. Thanks,Tony


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## Warhorse46 (May 11, 2005)

Toni, if you have 190k and that is the only code showing up then we have a good vehicle here. That is realistically how long one of the knock sensors should last. Around 200k. I'd be surprised if some other things hadn't shown up though.

Seafoam is a great decarbonizer,gas stabilizer, fuel treatment. You can get a can at most advanced auto parts, NAPA, etc. I was turned on to by an old dirt track racer turned mechanic turned parts store owner who had an oldsmobile he used this in after another mechanic had treated his car and he swore by it. So I tried a can and now I'm a believer in this stuff. It really cleaned the carbon out of the intake and made the truck run better. If you use it every 20 tankfuls or so and it will turn even the fithest engine into decent shape.

The EGR valve doesn't need to be replaced unless it is coding in the computer
this usually is what codes the knock sensor but the sensor itself can go bad at the milage you have on your's and it would just code the computer and make the check engine soon light come on. But it can make the truck run funny since the computer sees that nissans little money maker has a short in it. I would get one but I would get one on ebay or possibly a used one from a junk yard and see if that fixed it first before I ever bought one from the dealer. I gave only 80 dollars on ebay for one and that included shipping.!!!!


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