Hey Honda-Tech,

Here is my situtation that I need help figuring out.

Info on the car -
I have a 93 Scoupe GT Turbo 1500cc w/ GT15R.
Ported/polish head and intake manifold.
Upgraded turbo manifold.
Stock ecu/injectors/fuel filter and pump.
No CELs.

When I start the car while cold, it will idle around 1k rpm then jump up to 3k for a moment then back to 1k. Every time it jumps up it will hit a lesser rpm, ex - 2800, 2400, 2200, 2000, 1800, etc. until it reaches idle. It will continue this for 10-15 minutes until it is warmed up. Why is it doing this?


Next...

While driving, it will not let me give it more than 15-20% throttle. If I do give it a good amount of throttle it will bog down right around 3k rpm.

If I only slightly give it throttle I can go to redline. Why can I not give it more throttle?


I know this is not a honda question, but Honda-Tech is the God of all car information forums, so I figured I would see if I could get some help.
Thanks, Nick

 

Sounds like fuel type problem... You might want to try replacing fuel filter if you haven't done that and check your fuel pressure to make sure it meets the requirement for your model.

 

maybe iacv problem for the idle issue?