Hey guys, I'm sorry to bring up an old thread too.
But I've had exactly the same problem as what's been described here, from what everyone's saying I think it seriously could be my injectors.
This is my story I have a 1996 R33 GTS coupe that's been converted to manual and it also had a 1999 RB25DE NEO engine conversion with only 100,000 kms on it.
The previous owner did the conversion and I bought it off him cheap because he was moving to Australia (I live in New Zealand).
Anyway it's never been running right since I got it, it has been using way to much fuel (like 300-350km to a tank!) and has as much power as an RB20E or less... It makes a popping noise when under acceleration sometimes you can hear it coming out the intake and sometimes it backfires as well. Sometimes it seems like it's only running on 5 cylinders when it's idling and or driving. I've had the car for 5 months now and I've done the following things already to try and fix it.
Replaced spark plugs.
Replaced air filter.
Replaced fuel filter.
Replaced fuel pump.
Cleaned AFM.
Thought it was the coilpacks but they've been tested and they are sweet.
Checked TPS.
Put fuel injector cleaner in the fuel tank.
And recently I took it to see a friend of a friend who was a mechanic, he said the spark plugs looked like the engine had been running lean.
He did a compression test and the compression was perfect.
He gapped the spark plugs and advanced the timing and he seemed to think it was running bad because it was running lean.
Anyway after he'd gapped the sparkplugs and advanced the timing it had a whole lot more power than it's ever had it was wheel spinning from 1st to 2nd on WOT but still making the popping noise and not running perfectly smoothly like it should be.
I noticed an improvement in fuel economy too.
Anyway the check engine light has been coming on so I finally took it to the auto sparky and got him to plug it in. He said that the oxygen sensor was stuck reading rich so it was leaning out the air/fuel ratio and that I should get a new oxygen sensor.
So today I took the cam cover off to check the cambelt and then I put it back on along with the Cam angle sensor and I'm sure I put it on right and also fully advanced the timing like my friends friend did but when I started my car up it's running rough like it was before and the power and fuel economy is down from what it has been recently.
Then my new oxygen sensor arrived today and I was like yay this will finally fix it!
But guess what? I unbolted the old one and bolted the new one up and plugged it in and nothing changed! It's still running like rubbish and I'm beginning to want to tear my hair out!
Ugh this car is driving me nuts... It's my first Skyline and I've always loved them but I've had so many problems with it that it's almost made me hate this one...
Can somebody please help me?
