Hey guys. I've searched, but cant find anybody with this problem, maybe I havent looked hard enough, idunno.

I just put in my rebuilt engine a week ago, and its acting up:

My engine:
383 forged, mild cam (http://www.compcams.com/Technical/Se...umber=07-502-8), hasnt seen over 2psi boost yet, tuned by MadZ28, new plugs, fairly new but perfect Taylor wires, stock opti an coil (104k miles), stock fuel system.

When I first started it up, it had a bad idle. Found I had crossed a couple spark plug wires, fixed that and it was still bad, but a ton better. I adjusted the rockers, which were way tight. That helped a little more, but still a rough idle. It got better, the more I drove it, like the computer was learning how to run.

On Saturday, I had just finished adjusting the rockers with the engine running, to get it perfect, and all seemed well, so I pulled out of the driveway, and gave it gas to get up to speed (about 30% throttle) and it hesitated bad, like major misfires, but all 8, after giving more pedal, it finally kicked in and took off. I turned around, and went back to the shop where I was doing the work, and the whole way back, at like 10% throttle, it kept hesitating, and putting along. Got back, shut off and checked all the plug wires, they seemed to be fine. I took off, and it happened once more, but then was fine.

Then Tuesday, I went about 20 miles away to a store, and on the way back noticed that at certain TPS%, (cruising at like 10% throttle) it would have a slight stumble, enough to notice and feel it, but not enough to impact the speed. I started experimenting, and found that if I coast and then give it a bunch of TPS%, it would totally hesitate, there would be no exhaust sound at all that I could hear, almost like no combustion. I could give it WOT, and still nothing, until I let off a bit, then it would catch, and launch forward. Very wierd, its like I shut the car off then start it again, and take off, with the RPMs droping, but not a ton. Another wierd thing, is that I could hear the turbo spinning faster when it did this, like the engine is still pumping out exhaust, but no sound with it.

My fuel pressure guage stays steady around 40 psi, the whole time, and my A/F guage drops lean off the scale when doing this. No check engine light, or DTCs after checking.
After getting back, and getting my laptop, I Datamaster scanned while doing this again. Everything I see (I dont know a lot about it) seems fairly normal. I can email this to whoever, in uni format, or csv with help.

So Wednesday, hoping all is better, I drive around, dont really notice any problems, except for the usual rough idle, and more recent thinking about dying at stops. It catches itself, but comes close. After driving around, doing errands, it starts raining. I start going to another place, and it dies on me at a stoplight. I try to start it, and after 5 seconds of cranking, it fires up, and I rev it to like 2500 rpm, seems fine, I let it back down to like 1500, and it dies again. Start it again, after like 13 seconds of cranking, and pumping the pedal. Rev it up to about 3000 for like 10 seconds, and seems fine again, a tiny bit rough, but not much. I let it down slowly to shift to D, and it dies again. So I roll into the suicide lane to let people go past, and start it up again, about the same way, long cranks, pumping pedal, and this time keep it about 3000 for like 20 seconds, reving it up and down between like 2000 and 4000 rpm, it acts decent, stumbling a bit when going up from 2000. I let it get below that, and it dies on me again. So I let it sit for a couple minutes, and the same thing, it will run decent unless it gets below like 2000, coming down fast, or below 1500 coming down slowly. So I roll to a side street, and try again, still same thing. Wont run below 1500 rpm, and takes a while to start.

I sit there for about 13 minutes, and start it up again, and it runs pretty good. Holds the idle (though rough), and lets me drive home, about 1.5 miles, keeping a foot on the brake and one on the gas when stopped, it tries to die, but it doesn't do too bad. The last half of the way back, there are no stops.

Again, full fuel pressure, between 38 and 43, and the A/F is way lean, no SES light or codes.

I get home, and start studying on here, then about 30 minutes later, I needed to go to a friends, so I get in, starts up good, and runs decent. I go about a mile, and it dies at a stop sign. Same exact thing as before, wont run below 1500 rpm, hard starts. Wait about 15 minutes, start it, and it holds idle long enough to switch to D and go a bit, about 5 seconds, then loses it and wont work again.

So we go do stuff, and like 30 mins later, start it, and drive it back home, trying to die at stops, but I get home and that is that.

I have adjusted the throttle plate screw, but my IAC steps seem to be decent, and fluctuating. Im sure the timing is correct, as it can only go one logical way, and I did it about 2 weeks ago. My manifolds and cat arent red hot. All vaccuums that I can find are good.

I'm thinking its my opti, as the two symptoms are probably related, and wouldn't be anything else that I can think of. If I must replace the opti, I will do it with a Delteq, which is why I havent replaced the coil yet. Could it be the coil only?

Thanks for all help!

 

check your plugs... check vacums round the intake everywhere... make sure the wires are not burnt , make sure that your wires are on all teh way and what not... also try reseting the pcm after your do all that ****..