1996 2.4l rough idle

[Lostintime123]

I have a 1996 nissan pickup. I recently had to replace to MAF sensor. This solved my problem of not accelerating above 2,500 rpms but now the truck is having trouble idling. When I first go out to start it, it starts and idles just fine, around 1100 rpms. I'll drive it down the road a ways and once it warms up a little it starts dropping down to around 600 - 900 rpms and bounces up and down between the two. If I feather the gas it will stay running and run just fine but the minute I stop feathering the gas it starts idling rough again and will eventually die. I have sprayed the crap out of the throttle body with cleaner, that seemed to help a little, fresh tank of gas, I'm going to change the fuel filter and see if that helps. One thing I have noticed it sometime before it starts idling rough my radio will reset, could this been part of the problem? Maybe an electrical short?

[Lostintime123]

Alright just an update, I was out investigating and found a vacuum hose cracked, I replaced it and the idle seemed to level out, that is until I went and put the air cleaner back on. The second that I put it on top of the throttle body it started idling rough, take it off and it would idle fine...

[gecheveste]

hello i have the EXACT same issues on my 1996 nissan pick up. i also found a cracked vacuum line and replaced MAF. when i mess with the air cleaner my truck does the same thing. have you made any progress with finding a solution? i hope to share if i make any progress as well. i was told to look for a bad ground, so i will post any positive results .if i dont post then consider it a dead end.

[Lostintime123]

I haven't made any progress... Only thing I have tried was cleaning out the throttle body with seafoam spray at first that seemed to make it better, then it got worse. Looking around various sources I'm thinking that the idle air control valve may be the culprit. I wish I knew of a way to know for sure before I dropped 100 bucks on one

[gecheveste]

thanks for responding Lostintime123,
i forgot to mention that if i disconnect the MAF and it idles fine...i reconnect it and it started idling just like you described. have you tried disconnecting the MAF to see what it does to idle?
i have also been told its perhaps the idle air control...but no one is sure. i think i am going to order another MAF online and see if it fixes the issue. my gut feeling is that this will be the culprit. i will keep you updated.

[Lostintime123]

I checked the MAF and it doesnt seem to change anything. Have you had any luck? I think someone has messed with the Air/Fuel mixture screws so that probably has something to do with it. I cannot adjust the idle with the idle adjustment by the Idle Air Control valve so someone has messed with that and probably gotten it all screwed up. I don't even know where to start with trying to fix the idle adjustment screw, it looks to me like I have to replace the whole dang throttle body to fix that.

[Lostintime123]

I also would like to say that despite unhooking stuff and running it that I have no check engine light. I am thinking that the previous owner has somehow unhooked this, does anyone know where I would need to start to be able to check and see it the light is unhooked?

[Towncivilian]

The "service engine soon" light should illuminate with the ignition set to "ON". If it doesn't, the bulb is probably dead or missing. Since you have a '96 your Hardbody should have ODB-II. Most parts stores will pull engine codes for free, so try that and post them if there are any.

[Lostintime123]

I've got a buddy that is a mechanic and he has a code scanner and I am going to see if I can borrow it this weekend. I will post what I find. For now I took the actual air filter out and am driving it without one for now... Running like a champ without the filter in.

[Towncivilian]

I think it is a very bad idea to run without an engine air filter as that allows a lot of dirt and dust entry into the engine which can hasten engine wear (dirt can score cylinder walls, etc) and will cause your engine oil to load up with contaminants faster. Dirt and dust can also accumulate on the MAF sensor and cause damage, and your throttle body and intake manifold will get dirty as well. Should the engine backfire, flames can also come out of the air intake assembly. I would try to minimize driving without an engine air filter if at all possible.

[Lostintime123]

I finally got my hands on a scanner. These are the codes I got p0505, p1441,p0141, and p0446

[gecheveste]

ok i got an update for the rough idle on my truck.
i replaced the MAF and the rough idle has gone away!!

but now i have a new code to troubleshoot
the part that sucks is that i just replaced the MAF back in December trying to fix the rough idle.
i bought it on ebay and it came with a lifetime warranty, but when i contacted them to make a warranty claim they said that because it wasn't installed by a professional mechanic they would not honor the warranty.
i ended up buying another one from another supplier on ebay that didn't require it to take it to professional to install it....in the end, the rough idle is fixed.
if there was anything regarding the rough idle problem that you think that i may not have been clear on, feel free to ask.
about the new issue : the check engine light turns on when driving every once in a while, but the engine seems running great.
the code i pulled was PO1105
i guess that my time on this post is done .
wish me luck on the next issue.
I hope to be helpful around here.

[Lostintime123]

I just replaced the MAF not two months ago... I'm thinking that it has to do mainly with my idle air control... I just can't figure out how to get the thing off to clean it..

[Ding1]

if ya suspect vac lines,a cracked or one off which can also cause rough idles,get a cheap cigar,light it up and pull a couple hoses off and blow some smoke down the hoses and watch where it comes out.This will say where it or they are.Then MAFs are 'spencive,I have a can of MAF cleaner spray and a little " painters sable hair" paint brush for those electrode dookickies.The electrodes for those MAFs/air flow meters are delicate but if you clean them they can produce like new ones.

[sweetbeard]

if ya suspect vac lines,a cracked or one off which can also cause rough idles,get a cheap cigar,light it up and pull a couple hoses off and blow some smoke down the hoses and watch where it comes out.This will say where it or they are.Then MAFs are 'spencive,I have a can of MAF cleaner spray and a little " painters sable hair" paint brush for those electrode dookickies.The electrodes for those MAFs/air flow meters are delicate but if you clean them they can produce like new ones.

What is the location of the hoses to check and what hoses?

[gecheveste]

hi Lostintime123,
if were in your situation, i would check the MAF again. if you removed the electrical connector to it and it did not affect idle, that would be the good starting point. i had just replaced my MAf in december getting it ready for smog test but didn't really get to install it until april and thats when i noticed that idle wasnt any different when i disconnected the electrical connection to it. so basically it got a bad new MAF out the box. mine had the same symptoms when i would put the air cleaner on or off, it would changed the the idle performance but never smooth out. the MAF part number is AFH55M-12 for 1996 models After 06/96 and AFH55M-10 for earlier. if you need a photo of where it is and removal i can do that for you.

i hope to be of help.

[sweetbeard]

Please replace your fuel filter. I just fought the same thing, it sucked a** and spent about 500 bucks, got new parts and replacements that were needed for a tuneup, but it turned out to be the fuel filter. It's 5 bucks.

[Lostintime123]

I have already replaced the fuel filter... I think it sat for a while before I bought it and every tank of gas I keep dumping a can of seafoam in it and it seems to make it better..

[My1996niss]

I have 1996 Nissan pickup with rough idle I had replace mad sensor 3 times and last time I replaced my fuel temperature sensor went bad, any suggestions wether I need to buy a brand new one or keep trying with the cheep ones from e bay