DRAV3N

First off I'd like to say that I'll gladly post my ghost story asap.
Now,
Hello RPR, I'm glad I found this site, its already helped me with my car, but
I'm still having problems with her, so first off.

The Car, 87 CRX Si:
Please excuse the dirt. Haven't had the chance to get it all washed n such.
Only real body damage is the front right headlight which can be seen, and the cover in
front of the hood, not to sure about the name.
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^^ The car had been stolen once before so the column needs to be replaced.



I know too many pics, but I'm proud of the dirty thing.
One thing I know about these things is the rust can be bad, but
theres no rust on her. That I've seen anyway.
And I didn't do the rattlecan job, that was done by the previous owner. lol


Some background on it.
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Recently I was lucky enough to purchase an 87 CRX Si for $100 from my neighbor,
who was taking it to the junkyard that day. When I got the car it wasn't running(spark
no fuel). I was able to narrow it down to the Main Relay, I replaced it with one from
the same junkyard the car was headed too.
Got it to turn over and ran for a few days, then the alternator went out, tested bad so I
replaced it with an 89' alt. now she's up again.

The Problem:
--
Ever since I've had it, even before the alternator went out the PGM-FI light has been lit.
It turns on like a second after the car turns over. I checked the ECU and its throwing a
code for the TDC sensor. When I go to start the car up it has some trouble staying on. It will
turn over then die out instantly. After like one or two tries it'll turn over and be good to go.
The only other problem with the car that I'm having is that sometimes
after I let off the gas the RPMs will dip down to just above 0 and make the car shake, and then will
slowly bounce(Literally) back up to normal idle, which I have set just below 1.
Once in a while they'll dip so low that the car will die out.

The Question(s):
--
Will the TDC Sensor make the car act up in this way?
I know that other posts with similar problems and ECU codes have been told to replace the O2 sensor.
If thats the case would THAT cause those problems?
I looked at the location of it, and its sealed pretty well, I know that someone
posted on here saying to use a dremmel to notch it out and use a flathead to unscrew it,
but I'd like to make sure I'm replacing the right part.
Any help would be appreciated.

Again, ghost story will be up soon.