300zx TT, rough idol, misfire...

[Garth1994]

Hi guys, new owner of a Z and it's giving me a head ache....
When the car is started from cold it struggles to idol, missfires ( isnt running on all 6 consistently) and won't rev over 2.6k rpm.. Just holds back and starts to missfire.
The car runs very smooth once it reaches 60 degrees then runs fine at just over 1k rpm... But does sound like it misfires slightly every few seconds, and still won't rev over 2.5k rpm. Still holds back and missfires

Please help it's driving me insane

[itsa300zx]

Run the codes and check the mass air flow meter under the front nose panel.

[Garth1994]

Run the codes and check the mass air flow meter under the front nose panel.

I checked the codes, and it's giving me 55
Checked compression 156psi, has fuel and spark...
Yet to test Maf or temp sensor :/
This car is running me

[DCaff300ZX]

You have corroded connectors at the injectors, IACV, or PTU harness most likely. Carefully remove those connectors and you will most likely find green corrosion inside which will cause intermittent and faulty connections which will be a misfire or two, or drivability issues from the IACV.

[nexus08]

Yeah what D said. While idling, you can place a long screwdriver on the top of each of the injectors and listen for a clicking sound to see if all the injectors are firing right. All of my connectors were nasty. I got a small file and cleaned those up. I didn't put anything on them afterwards, but I've heard some put on some dielectric grease to help keep them clean and lock out moisture.

As to not going over 2500 rpm, these cars have a "limp home mode" they go into when they aren't getting readings from various components. Like itsa said, my money would be on a bad connection for the MAF. I cleaned my MAF but didn't get a good connection when I reconnected it, and it did the same thing. Opened her up again, and replugged it in and the problem went away.

[Garth1994]

Thaks guys, will try all of the above today and see if I can cure It:) my maf has fairly clean looking connectors, ptu has alot of green on pin 5, will do injectors

[Garth1994]

Yeah what D said. While idling, you can place a long screwdriver on the top of each of the injectors and listen for a clicking sound to see if all the injectors are firing right. All of my connectors were nasty. I got a small file and cleaned those up. I didn't put anything on them afterwards, but I've heard some put on some dielectric grease to help keep them clean and lock out moisture.

As to not going over 2500 rpm, these cars have a "limp home mode" they go into when they aren't getting readings from various components. Like itsa said, my money would be on a bad connection for the MAF. I cleaned my MAF but didn't get a good connection when I reconnected it, and it did the same thing. Opened her up again, and replugged it in and the problem went away.

Any way I can test the maf to rule that out?

[nexus08]

Hey was just reading another thread and remembered when my ecu coolant temp sensor was bad. It REALLY acted up bad, kind of like you are describing. Super easy fix as that connector is right in front on top of the radiator. I cleaned the connector and replaced the sensor (probably could had just cleaned it, but it was cheap and in stock at Autozone) and all was right with the world again.

[Garth1994]

Hey was just reading another thread and remembered when my ecu coolant temp sensor was bad. It REALLY acted up bad, kind of like you are describing. Super easy fix as that connector is right in front on top of the radiator. I cleaned the connector and replaced the sensor and all was right with the world again.

Awsome il try that first as it the cheapest! Thanks it took me a few days to plumb all the vac line up as it had alot of money spent (forged engine) but a f*** retard worked on it this. Iv Had it in bits going through the hole car

[DCaff300ZX]

+1 to the coolant sensors, def worth the checkup!