replaced gas tank (from non vtec 95 4door) - swapped my old gas tank internals to donor tank.
All well except sometimes on first drive (irrelevant cold, warmed up or still warm from previously driving) it will go full retard for about 30 seconds.
Basicaly if I keep it around 2~3k its fine, no acceleration though, if I can blast past up into 4k range it will seemingly smooth out by sheer force (very erratic acceleration/idle/TB popping/backfire, jerks like it will stall) but like I said after 30 seconds of this it smooths out and acts fine.
Now I know I need to do an ignition tune up but I feel its a fuel mishap due to a code 45 with the CEL.
Been trying like hell to get video of tach/speedo to post but seems every time I record it dosn't do it (so I do it all the time now so I don't have to deal with it ^_^)
Any thoughts?

 

Beg/Borrow/Steal a fuel pressure gauge. Attach it to the fuel rail and watch the fuel pressure. If it fluctuates then the pump is probably crapping out. You may also artificially raise the PSI from the pump to check if the FPR is crapping out by pinching the return fuel hose AFTER the FPR.


Why was the original tank replaced?
If it was damaged or punctured the pump(or other hanger parts) may have been damaged as well.

 

Get a scanner and scan it. I've never even heard of a code 45 coming up. 

 

I'm in the great rusty north, I'm also a tow truck driver with a shop at my disposal so I noticed the rusty brake and fuel lines immediately after getting it up on a lift to investigate why it leaked fuel.
Replacing the lines I discovered the tank was riddled with rust holes straight through the steel, Seemed my cheapest replacement would be $115 so I opted to strip the 4door that had been in our impound yard for nearly 3 years.

Yesterday I hooked up our scan tool to it and poked around in its brain, during active passive scanning everything was normal, stored code 45 was a lean mixture - cleared code hasn't come back yet, more than likely its from when the fuel supply line was sucking air through.

The ABS light however is a mystery!
Couldn't get handheld to play nice with ABS unit, defaulted to blink code, 3 blinks, wtf does that mean? three long (or short) blinks and then it loops back to the beginning.
Head mechanic says today we'll hook it up to mother and we'll pin it down.
Helps to have 1/2 a million dollars in tools at your disposal.