V8 swap question

[sparkyjdp]

Well I am new here and have already started my swap, in fact it is already in. I went with a 5.7 vortec out of a 98 chevy c1500. I sent off last week to have the computer reprogrammed and got it back yesterday. Put it in and it runs rough, took it for a drive it shifts fine just is lacking power a kot of power. I was doing 55 at the bottom of a high by my house and by the time I hit the top it would only do about 30. read the codes and have a multiple cylinder misfire. any thought on this?

[phatmaxx87]

did you do any base engine work? How many miles does the 5.7 have? Did you replace the spider injector? Any blow-by? Let us know the history of the 5.7

-Vance

[sparkyjdp]

I bought the engine from a salvage yard in witchita ks. It has roughly 168,000 miles and ran when pulled. I dropped it in the van and got it to start but roughly, the next morning I could not get it to start. I then pulled the spider asembly out and cleaned it ( soaked in carb choke cleaner over night then installed it. That is about all I have done to the engine and all I know about it.

[mikedamech]

What year is your van?

[sparkyjdp]

van is 96

[Smiliesafari]

Try a stock ECU to see if it makes any difference. Welcome to the site. Post some pics of your ride.

[sparkyjdp]

I tried the stock ecu and took it to a dealer to get the programing for it they wouldn't do it so I sent it off to get reprogrammed. It runs the same before and after the programming. also when it is a little warm it starts for a bit then stalls.