Rep Power: 0

Hello,
I recently purchased a 'very used' 1997 Civic EK sedan with a D15Z7 engine. The car had high idle and kept revving high on its own. So went to the mechanic and did the following:
1. Replaced the IACV - result, car was still revving high although less frequently.

Pulled the car a little on the highway to 6k revs and the engine shut off with the Oil pressure and Battery lights on. Also this time the Check engine light came on and it stayed on. Went back to the workshop. Checked the code and it was a bad throttle-body sensor ( the one at the bottom of the throttle body).
2. Replaced the throttle-body - result, no more problems related to auto-revving high.

However, found some leaks on the intake so replaced the seals and engine noise went down by far. The car felt nice for a few seconds that I drove. It feels smooth compared to before.
Now the engine keeps shutting off when I get off the throttle, or slow down, or come to a stop. When cranked, it turns on again. I can feel that it's a tuning issue, but we've spent hours tuning it. It doesn't shudder or shake, I tried increasing the Idle a little on my own and still it keeps shutting off.

My mechanic suggested that the engine needs to be replaced.
So I'm calling on all the Honda Gurus. Please help me understand what's wrong with this engine. I read on a different forum that it could be the MAP sensor. I haven't explored that yet.
Would really appreciate your input.
Thanks

 
Rep Power: 244

Does it have any codes at the moment?

Was the IACV a Honda one or aftermarket?

 
Rep Power: 0

It's not giving any codes at the moment. The IACV is from an old d15 engine that has been reconditioned. We don't get aftermarket parts in Bangladesh, or rather expensive.

Since my original post, the idle has become rougher, and the Oil & Battery check lights come on as the engine stalls. I've seen the ABS flash on a few times as well.
I feel like I'm inside a nightmare...

 
Rep Power: 0

It's not giving any codes at the moment. The IACV is from an old d15 engine that has been reconditioned. We don't get aftermarket parts in Bangladesh, or rather expensive.

Since my original post, the idle has become rougher, and the Oil & Battery check lights come on as the engine stalls. I've seen the ABS flash on a few times as well.
I feel like I'm inside a nightmare...

 
Rep Power: 222

Bad alternator?

 
Rep Power: 0

I've been thinking about that, I will check that out.

Thanks

 
Rep Power: 0

Checked the alternator and the wiring yesterday. It's working fine. Changed the spark plugs for good measure. I'm still having the idle problem. However, it has changed a little. After cold cranking it, the car doesn't idle well in the morning, so I adjusted the RPM to 1.5-1.8K, cause by the time I commute back to home, the RPM gradually falls to less than 600 rpm over the whole day and the car stalls. This is my temporary fix, to keep the car running.
I only drive for about 1 hour in traffic in the morning and in the evening. Overall, the rpm falls by 1k by the end of the day. This is really weird.
Also, I've noticed the smell of engine oil from inside the car. Some times the exhaust's showing white smoke... we all know what THAT means...!

Maybe I should just save up money and get an engine...

 
Rep Power: 244

Maybe do a compression test and see what kinda results you get.