Rough Idle when coasting or at a stop

[Penalozamax]

Hello everyone, im new to this forum

I have a 1990 nissan 300zx NA 5 Speed

When I bought the car I drove it for about 25 miles no problems at all,

Left it sitting for about 5 months, just registered it after I installed a new megan racing full catback exhaust and some 350z rims.

Now being the second day I drive it, it sputters when ever I floor it. As well as it stalls when I cruise with the clutch in, When it wants to it doesnt. The Rpms go low and when it wants to it struggles to not die out and the alternator belt screeches.

Wondering what you guys think could be the problem, I have a non running 300zx Na aswell so I have all the parts to replace if needed

Another thing is im driving without a front bumper at the moment due to it cracking last week in case that could be the problem

[Penalozamax]

If you are seeing this post please comment and give me some ideas! its my daily car and want it to be fixed asap thanks fellas

[solaire]

Check your basics. Does it have old gas still or a fresh tank of 93 octane? What's the idle speed? May be set too low causing the stall. Sputter could simply be injector connectors, ptu connectors or CAS connectors. These like to corrode with age. The terminals in the CAS tend to spread causing a loose connection also. This can cause the stall also. What spark plugs are you running?

[Penalozamax]

I will def look into those things, Another thing I had a doubt on, was when i took the factory exhaust system off there were 2 hoses that connected to the down pipe/cat since my new exhaust system didnt have those connections i simply left them hanging does anyone know what those hoses are for?

[solaire]

That's a secondary air system that was used to put air into the exhaust to pass emissions. It's not really necessary but I'm not sure if it could allow something like an intake leak? I'm not too familiar with this system since it's pretty primitive and isn't used in many vehicles anymore. Did you drive the car before and after the exhaust then develop the problem?

[Penalozamax]

secondary air system hmm, Dont know if that could be the problem I got the exhaust system from my donor car and it did not have those hoses, So im a little skeptical when I bought the car it had the stock system and drove fine while i brought it home, I shouldve test driven it more to see if the new system is affecting it, Yesterday when i drove it, it was raining hence i do not have the front bumper on im wondering if the intake or anything is causing this problem. or in general if too much air is getting into the intake or idk im confused

[solaire]

unless you run through a puddle, water up the intake on most nissans will usually not make it to the engine because it'll fry the MAF before it gets there.. not a good idea

[nissanfreak12]

Have you check for code?

[hendersonw2012]

I've been having the same problem, mine got so bad that it won't even idle anymore. I got codes for coolant temp sensor and ignition signal circuit. when i replaced the coolant temp sensor it helped a lot but then it got bad again. try checking your codes and let us know what happens. I'd like to be able to compare our cars since there seems to be similar problems haha