1989 240SX randomly dies in park, and now dies in drive.

[Tieny]

Ok Guys I'm new here and have been reading lot of threads. Any help would be great and thanks! I don't know much about cars at all.. So I have a 1989 240sx (AUTOmatic transmission) stock ka24e giving me some problems.

LONG STORY SHORT:
the idle would sometimes drop low, the engine would shake like it wants to die, and the idle would go back up to normal. It does this a couple of times until it actually eventually died...
The car would never die in drive though, but recently I think since the weather has gone from 30 degrees to 80 degrees.. its starting to die in drive when I'm making a slow stop or turn.

What do you guys the problem is? So far reading all the threads I've found, I narrowed it down to a Vacuum leak, MAF sensor, or IACV.

Fuel injectors have been cleaned and tested working already, spark plugs replaced, fuel pump is good, TPS is good.

If you want the long story, whats happened so far, and how the problem is getting worst read below.



LONG STORY:
I recently got a 1989 240sx a couple of weeks ago. Fuel injectors have already been cleaned and tested working. It ran okay but I did notice once the idle dropped a bit when I parked, the engine started shaking and the idle went back up to normal. It only happened once so I thought it was ok. The weather is cold at this point around 40 degrees F.

Two week later, driving it okay I made about 3 stops around the neighborhood, turned off the engine, turned it on, drove away fine. Until the third stop, I turned on the engine reversed then I noticed the engine completely died and shut off.. I turned the key and restarted it and it ran fine like nothing is wrong with it. Drove home and parked and tried to get it to happen again but it didn't. So I just sat in the car in park trying to figure out whats wrong and then I noticed the idle started to drop low, engine shaking and went back up. It did this a couple of times until it dropped low and it didn't want to go back up and it just died in park.. I tried to turn it on again, cranked the engine but it wouldn't turn on. Came back about 3 hours later to try again turned the key, it started fine, idle seemed fine too and didn't drop anymore. (Like nothing was wrong ?)

Drove it for another couple days fine. No problems. It was only when I noticed that if I made alot of stops around (turn off the engine and then back on), and then parked and looked at the idle it would do the dropping and shaking again until it eventually died.. But the first trip i make after haven't driving it for awhile was fine in park.

Then couple more days later (about 3 weeks from when I got it now) I made about 4 stops, went to turn on the engine, it would start and then idle drops way low and dies right away... did this about twice, then tried again and even gave it a little gas to keep the idle up but as soon as I let go, it just dies again. So I waited a couple of minutes, turned it on again and tried to put it in drive before it died. Took a couple of tries before I got it in drive before it died. Once I got it in drive it'll stay on but it'll be shaking so hard like it wants to die but it can't. I drove around the lot for about 5 minutes and the entire car was just shaking hard.. So I started driving home, after 10 minutes the shaking finally stopped and it was driving normally again. I finally the car home, parked it and it idle okay (don't remember exactly).

(week 4) later I would turn it on and off fine.. it starts normal, idles normal but every now and then it would drop a bit and back up (wasn't as bad). I haven't been driving it though.

(week 5) The weather is about 80 degrees. Tried out the car, it turned on fine, idled fine, left it in park for awhile and theres was no problems? Testing the car a bit, turning on and off the engine about 4 times, reving it, and it didn't seem to show any problems. So drove it around fine until we made a turn to park and then the car just dies while in drive (this never happened before). Drove it back home and parked it, watching the rpms and it would start showing the problems again. (dropping idle, engine shaking, repeat until it eventually dies.) Thought the dieing in drive was a fluke, so I drove it around the neighborhood the next day. it was now hot outside like 90 degrees. Turned on the engine and the rpm was around 500. Thought it was normal since it was hot as hell. It would usually start around 1100 rpm when it started cold and drop to 500 when it warmed up. Drove it fine, Until I was slowing down to make a turn and noticed the steering got really hard and the rpm was at zero.. Turned the engine back on fine and drove it back home. And that is up to today so far....

[biggie]

Spray some carb cleaner in IACV first. If that doesn't help move to other things.

[Tieny]

So just started the car today, idles at around 700 steady no sign of symptoms today... Test drove it fine, didn't die, shut it on and off a couple of times. I watched the idle for about 30 mins and there doesn't seem to be any sign of the problem... I was messing with the intake and vacuum lines a bit before testing it, and unplugged and replugged the MAF sensor too. Not sure if it did anything but I'm pretty sure the problem is still there somewhere.

Just bought some seafoam spray and fuel system cleaner, I'll keep you guys updated

[Tieny]

I just cleaned the MAF sensor, found the gasket on the MAF to the air intake housing was broken. I cleaned the throttle body and the IAC valve. The IAC was really dirty... took a good half hour to spray out all the carbon build up out with carb cleaner. Reattached everything, started the car and doesn't seem to be anymore problems (At least I don't think). It even idles just a bit higher than before.

Weather is warm today, when starting the car it'll always start at 1400 rpm for a few seconds and drop down to a steady 850-900 rpm in park and neutral.
In drive and reverse its getting a steady 600-650 rpm. So far no more idle drops or stalling, took it for a test drive and its good so far.

[Tieny]

Alright so the cars been running fine and normal since my last post. But now I just went to get emissions, now the car will cold start with a low idle..

Start the car cold and everytime now itll idle straight at constant 550 rpm.. and itll slowly go back up to normal idle after warming up. If I put it in drive itll drop to 400 or less rpm and the car stars shaking like it wants to die again if i dont let it warm up. Unlike normal idle where it should idle past 1000+ during cold start and drop to normal idle as it should.

This occured RIGHT AFTER getting my emissions test. So what did they do??? I'm sure they adjusted something back to factory specs in order to do the emissions or they messed with something...

[AeonTorpor]

They check the emissions of the car, the fuel cap and the sealed gas system for leaks via the fuel cap. They don't adjust anything. I've been having the same problem off and on for probably 2 years. My car was driving perfectly yesterday, but today it sputtered often between 2-3k and almost stalled on me a few times. I've completely cleaned the EGR, PAIR and IAC. I then completely removed the PAIR system and sealed the inlets/outlets. And I still sporadically have this problem.

Now granted. I'm seriously, seriously lazy. I haven't changed every single vac line, checked the MAF seal/ cleaned MAF, etc. However, it HAS on the other hand still managed to pass emissions and make it another 35k miles in the last year and a half. Sooo, I'm not worried about it. I'll deal with it when I rebuild my engine. Buuuuuut, I'd LOVE to hear how you fix the issue, if you ever do. Sorry, this long winded post is such a let down.

[Tieny]

Still having the problem with the low idle start up.

I just found out that if I disconnect the iacv there is no change at all... symptoms stay the same. Start up, low idle, and goes back to normal idle when warmed up. So i'm figuring that it is the iac valve. Measuring the two pins connecting to the solenoid part, i'm getting the 12V from the battery. I'm not sure if the iac just went bad or not.. But i'm just very suspicious of the fact that this happened after getting my car back from emissions. And the fact that it took almost 3 hours for them and just to tell me they couldn't even do it because of an exhaust leak... =/

For the initial problem I stated in the beginning I'm concluding that cleaning the throttle body did the trick to fixing that. The car has not had any more weird dropping idle and stalling since. And I'm currently running with the idle control valve disconnected with no problems other than the low start up idle.

[Tieny]

Alright guys, haven't had any problems lately (besides the exhaust leak and heating floor, probably from the converter). I feel like it is running rich, its been eating up gas alot. Today I was driving and coming to a slow and noticed my rpm was going unsteady around 200-300 rpm (with the shaking). Turned in a parking lot, and restarted the car but the idle is still going low and unsteady like it wants to die.

Just let it sit for a minute, unplugged and replugged the MAF and it was idling a little higher but the car was still heavily shaking. So I continued to drive it for a bit and notice there is a HUGE loss of power. I could barely accelerate through a slight uphill...

Alright got home car still shaking hard, but I found something interesting. If I twist the fuel injectors a bit, the shaking would either get worse or disappear. So I'm sure I've found the problem. I gave each injector a hard twist until one of them where the shaking and rough idle was gone. Gave the car a test drive and i have the power back.

Would this indicate bad fuel injectors? Also bad O-ring seals or could be a bad connection on one of them. I was messing with the harnesses on each injector but there doesn't seem to be any change. Only twisting them would cause the bogging shaking. The thing is that its not just the one injector, I twisted other injectors and sometimes it would cause the shaking also.

(If it is bad injectors, this would kind of explain the low rpm bogging, where If I step on the gas at a certain point, usually at starting speed, there is a slight shaking, like pulsing )

[Tieny]

New update. I found out the problems with the fuel injectors were just bad connections. If I put some pressure where the wires are connected to the injector the engine shaking would happen. This happens on all the injectors (some harder then others to occur) So I'm guessing I have bad connections to the injectors. Tried cleaning the pins with a wire blush and some electronic cleaner but it'll still misfire if I move the wire around. Guess the wires are rusted bad and I'll need to replace them.

Other day was just messing with the fuel injector connections to make sure its in good contact. I notice the idling felt a bit rough almost like its pulsing? Drove it for a bit and I slowed to a red light and the rpm dropped to 200-300 and started shaking about to die... so I put it in neutral and revved it, the IACV kicked in and kept it up at 1100 rpm for a second but then it dropped and started fluctuating crazy around 600-800.. So I hit the gas and drove to a parking lot, the acceleration was rough (but it didn't feel like it lost any power as before), thought it was the fuel injector connections again, wiggled them around but the idles still moving up and down, and the car still wanting to die when put in drive... So I disconnected the MAF, started the car, car starts for a two seconds and dies, and replugged in the MAF again. The problem seems to be better after that, idle is soild, (this is what I usually do when I have this problem) so I drove it back home.

****I did notice that everytime this happens with the fluctuating idle and shaking stalling, that there's a ticking noise. right on the metal cover above the exhaust manifold under the spark plugs. (sounds like liquid dropping onto the metal and evaporating, or better example like when you install a new exhaust and itll heat up and expand and it cools down it'll make a ticking noise since the metal is cooling and shrinking back down.) a Clue?

But I just replaced the MAF sensor today - No more hesitation with acceleration, it feels perfect smooth! Uncertain if itll fix the random rpm drop and stalling. I still have the acceleration pulsing at that certain low rpm range though.