03-06-2019, 01:29 PM
Drives: 1997 Skyline GTST
Join Date: Jan 2018
Location: Newfoundland, Canada
Club ID#: 87570
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Warm Idle Issue
Hey everyone, I'm having an issue with my 1997 R33 GTST S2 and was hoping you knowledgeable people can help guide me to what to I should do to figure it out. I have searched the forum and have found problems similar to what I am experiencing however no one with the same issue that I can find. My issue is once my car warms up it begins to idle rough. I notice a drop in RPM's anywhere from 100 - 200 when this happens. I also can hear an audible pop from the exhaust and can feel a shudder throughout the car. This happens only when the car is warm and stopped at idle. It happens every 30 seconds or so and I'll experience multiple drops over a span of 5 seconds or so. One thing I have noticed recently while having the hood popped while this is happening was each time the RPMs drop I hear a single loud tick that seams to be coming from an area near the firewall however I cant pinpoint exactly where it is coming from. I have also noticed that the idle gets rougher when I have either the heat or AC on. I'm racking my brain trying to figure out what can be the issue as the car starts and runs perfectly.
I should also mention I purchased the car from Japan and had it shipped to Canada through a broker so I don't have much history on the car but from what I can tell it is basically stock with the exception of a Blitz turbo timer and the muffler appears to have been replaced with a NISMO brand.
During my searches throughout forums I have come across some things to attempt and here is what I have done in attempt to fix the problem however it still continues
- Re soldered and cleaned AFM
- Cleaned AAC Valve
- New spark plugs gapped to 0.8
- Cleaned coil packs
- New fuel filter
- Checked fault codes through the dash which showed no issues
- Checked engine bay and hoses for leaks
- Rough idle no change when unplugging 02 sensor
- Fresh oil change, old oil appeared clean and free of debris
- New Optima yellow top battery as the old one was weak
When the vehicle arrived in Canada last year I also had to re solder dash gauge connections due to gauges not working and soldered in new relays into the ABS module. I have recently ordered a consult cable to help with diagnostics of the car so I am just waiting for that to show up. Any suggestions on routes that I can take to help figure out this issue would be greatly appreciated!