I have an 89 Chevy that I recently put a 350 motor from a 91 in. Since then I have had nothing but problems. It will run fine for a few days, then will die. Once it does it will not start back up. Let it sit for a day or so and it will start back up. Replaced coil, and ignition module. Still having the same issue. Hooked a code reader up to it, and it displayed code 32. Replaced the EGR valve with valve off of 89 motor. Continued to have the problem. Replaced ECM and ran fine for about 2 weeks, then died again on me. I am now getting an error code 52 along with the 32. Dont know a lot about throttle body so I'm at a loss. Something is causing it to stop getting fuel. Anything else I should look at???

 

Just for laughs, check the fuel pump and fuel filter. Only cause this sounds a lot like what my 88 did when the Fuel Pump was bad. Would start fine, then die and take a couple days to restart. Until I let it go too long and it died and didn't start back up lol.

 

Both are new along with the fuel relay and fuel sending unit. Taken it to 3 different mechanics and no one can figure it out.

 

Double check all of your grounds.

 

Did you only use the block and heads from the 91 or also the fuel and air delivery systems? Do all the sensors cross over from both years so that the 89 computer will read data from the 91 motor?