Hey guys, I'm beyond stumped. My all stock d16a6 outfit has run well for years, and this problem has started recently and gradually.

Symptoms I DO have:

-Completely gutless. Takes forever to accelerate at any speed or in any gear.
-Runs out of power and will not rev past 3.5k to 4k rpm while in gear. (However, can redline if in neutral.)
-CEL codes 1, 1, 9, 16 when I hit about 60mph on the freeway. (1 blink - pause - 1 blink - pause - 9 blinks - pause - 16 blinks - repeat)
-Codes clear on restart, and will never come back if I stay under 60mph.

Symptoms I DO NOT have:

-No loss in fuel economy. (Most recent tank was 31mpg city, including AC.)
-No hard starting
-No rough idle
-No smoking or funny smells
-No stuttering/missing

What I have checked/tested so far:

-Cat is not plugged (is actually punched out)
-Air filter is clean
-Fuel pressure tested (holds steady at 42psi)
-FPR tested ok
-Timing checked and is perfect
-TPS tested perfect
-Brakes are not sticking or anything
-Checked fuel injector connections
-Tested compression ok (outer cylinders - 180psi, inner cylinders - 170psi)
-Checked spark plugs, gap correct, all 4 are perfectly clean

SO.... what else should I check? Could it really just be my 02 sensor going bad? (It seems like I'm missing most of the symptoms related to a bad 02 sensor.)

 

Sounds exactly like a clogged exhaust. Can you unbolt the exhaust before your gutted cat and go for a test drive? Possibly some junk from the cat blew through into your muffler.

 

I have/had a very similar problem with my d15z1. I drive 100 miles per day on the FL turnpike and from time to time if I went over about 85 I'd get a check engine light and then it wouldn't rev past 3500rpm until I shout the car off (while still at 80) and resart. It would only happen once every few days. I'm having trouble pulling codes so I never got a a code. Since I replaced my alternator I have only had it happen once (and it's been over 6 months) Hope this helps.

 

I wonder if there's an issue with your injectors or injector wiring. When it's idling, put a long screw driver on the body of the injector, and put your ear to the end of the screw driver to make sure it's 'clicking'. If it's not, you've got a problem. Faulty injectors can cause an 02 code too.

Code 9 is a cylinder position sensor i think? Usually caused by bad timing, bad dizzy or an open in the dizzy wiring.

Start with your injectors, move to your dizzy. Your 02 code will more than likely be caused by this.

It's odd that the code 1 repeats itself however. Are you sure you're not mixing up the short/long LED blinks?

 

check throttle position sensor! verify that it is working correctly! had this issue and i just had to replace it hope this helps

 

Thank you everyone for the great replies... especially you 4drEF!

Here was my problem.

 

You put steel wool in your what?

 

I didn't do anything... that is what I found stuffed tightly in the bend of my exhaust pipe just before the muffler.

I had to hacksaw the pipe open to get it out.