Hey guys, I just want to start of with thank you for the help and putting the time and effort to help me. Ok so I have a 1986 nissan 720 rwd manual transmission . The engine is stock besides having spark plugs and all the things we usually need to change. So I have been have a problem with my car. So while I drive my car for a while a strange lag begins to happen when I start slowing down. And I like to double clutch down shift, and I make my way only to 2nd. It then starts to bag fire a little bit like popping sounds. When I come to a complete stop, I feel as if my car is about to stall on me. The idle lowers a lot! So I have to rev the rpm then I turn the switch on and off quickly and then it goes away. While I rev the engine it lags as if it doesn't want too. It also decreases the power a ton. And I forgot to mention this, but while I'm driving my car jerks and feels as if it's about to turn off. Idk if it all began when I got a new distributor but who knows. I had recently changed the spark plugs to ngk premium i believe and that wasn't it. ALL HELP NEEDED PLEASE!!!

Welcome to NICO! Hopefully we can help you out. I've broken your post into sections to try and get a more clear picture. I know you're trying, and we'll do our best to help you sort it out. If you could get a video, that'd help too!

720guy4life wrote: Hey guys, I just want to start of with thank you for the help and putting the time and effort to help me. Ok so I have a 1986 nissan 720 rwd manual transmission . The engine is stock besides having spark plugs and all the things we usually need to change.

So I have been have a problem with my car. So while I drive my car for a while a strange lag begins to happen when I start slowing down. And I like to double clutch down shift, and I make my way only to 2nd. It then starts to bag fire a little bit like popping sounds.

Out of curiosity, why are you double clutching? The syncros should be able to take care of the job for you. Do you find that the engine still backfires and pops if you just let the car slow down in neutral or the gear that it was last in?

720guy4life wrote:
When I come to a complete stop, I feel as if my car is about to stall on me. The idle lowers a lot! So I have to rev the rpm then I turn the switch on and off quickly and then it goes away.

What switch are you referring to? How far does the idle dip?

720guy4life wrote:
While I rev the engine it lags as if it doesn't want too. It also decreases the power a ton. And I forgot to mention this, but while I'm driving my car jerks and feels as if it's about to turn off. Idk if it all began when I got a new distributor but who knows. I had recently changed the spark plugs to ngk premium i believe and that wasn't it. ALL HELP NEEDED PLEASE!!!

This sounds like the clutch is slipping, or you have an issue with timing. Did you retime the engine when you replaced the distributor? You may want to get a timing light on that bad boy and make sure its correct before you detonate and do damage.

Wondering if maybe the timing is off - Although, with that truck, it could be a few things.

I'm thinking vacuum leak as well. Let's go through the underhood area, and check every rubber vacuum hose. Make sure there are no "open" nipples, and no loose or cracked hoses. You should be able to hear a hissing sound, but manually check each hose by hand and feel / listen for rushing air sounds.

You can also spray some starter fluid in any suspect areas - if the idle increases, your problem is close by.

Lastly, do you have the factory service manual? That's going to be a huge help: www.datsunservicemanual.com

Welcome aboard!

Idouble clutch to down shift so my gear won't grind. I have a horrible tranny ha. I noticed that my car backfires more when down shifting. Then in neutral.
I also meant as turning the car on off with the key switch.

My timing is fine. I had my brother help me with the timing flapjap

And AZhitman I will get on that vacuum

frapjap wrote:Welcome to NICO! Hopefully we can help you out. I've broken your post into sections to try and get a more clear picture. I know you're trying, and we'll do our best to help you sort it out. If you could get a video, that'd help too!

720guy4life wrote: Hey guys, I just want to start of with thank you for the help and putting the time and effort to help me. Ok so I have a 1986 nissan 720 rwd manual transmission . The engine is stock besides having spark plugs and all the things we usually need to change.

So I have been have a problem with my car. So while I drive my car for a while a strange lag begins to happen when I start slowing down. And I like to double clutch down shift, and I make my way only to 2nd. It then starts to bag fire a little bit like popping sounds.

Out of curiosity, why are you double clutching? The syncros should be able to take care of the job for you. Do you find that the engine still backfires and pops if you just let the car slow down in neutral or the gear that it was last in?

720guy4life wrote:
When I come to a complete stop, I feel as if my car is about to stall on me. The idle lowers a lot! So I have to rev the rpm then I turn the switch on and off quickly and then it goes away.

What switch are you referring to? How far does the idle dip?

720guy4life wrote:
While I rev the engine it lags as if it doesn't want too. It also decreases the power a ton. And I forgot to mention this, but while I'm driving my car jerks and feels as if it's about to turn off. Idk if it all began when I got a new distributor but who knows. I had recently changed the spark plugs to ngk premium i believe and that wasn't it. ALL HELP NEEDED PLEASE!!!

This sounds like the clutch is slipping, or you have an issue with timing. Did you retime the engine when you replaced the distributor? You may want to get a timing light on that bad boy and make sure its correct before you detonate and do damage.

double clutch to down shift so my gear won't grind. I have a horrible tranny ha. I noticed that my car backfires more when down shifting. Then in neutral.
I also meant as turning the car on off with the key switch.

My timing is fine. I had my brother help me with the timing... flapjap

I fixed the timing. And I will get on the vacuum hoses. I'll check that. I was wondering if the hesitation could be because of a cracked fuel filter or fuel pump?

I kept thinking timing the entire time I was reading the thread.
I'm not sure if there are any sensors that could affect the timing though. Its been a while since I've been under the hood of a 720. I forget, but do those have dual plugs per cylinder? You mentioned a dizzy swap... are you sure all the wires are back where they need to be?

Have you checked valve timing as well?