eng swap problem

I swapped in a 93 4.6 into an older car. the car i pulled it from ran great and idled great. after the swap i need to feather the throttle to keep it running and it acts like its running lean. The only thing different is i put on a cone filter with adapt infront of the mass air flow sen and removed the all 4 cats. Why is it running so badly?

I swapped in a 93 4.6 into an older car. the car i pulled it from ran great and idled great. after the swap i need to feather the throttle to keep it running and it acts like its running lean. The only thing different is i put on a cone filter with adapt infront of the mass air flow sen and removed the all 4 cats. Why is it running so badly?

What 4.6 did you swap, from what car into what car?

the eng came from a 1993 crown vic. I installed it into a 1957 cadillac.

Huh. Never heard of that one before. Is it a common swap? Something may have gotten messed up in the physical swap itself. If you think it is running lean, get a wideband and see what your read out is. If you are running lean, then its either the AFR needs to be tuned for the motor, or you may be having issues with your filter sitting on the MAF.

Great advise CassiesMan. That is a weird swap.

The reason i used the crown vic is because it was the first fi pre obdII car that i found that ran great and was cheap. i didnt matter what it was out of i would have had to make mounting brackets for any engine. i pulled every single wire / harness off the crown vic and connected them all on the 57. i wanted to make sure there were no wiring "missing signal" issues.
I have been told that the tps needs to be adj due to the extra airflow from the air filter i installed, however it is fixed on the 4.6. I have also been told that when i removed the cats it removed a certain amount of back pressure the eng needs to run correctly. I am thinking more and more that that might be the most probable reason for my problem. Has anyone ever heard of that before?
Kurt

I have not heard of that before. You might also check the vacuum system. If you faild to connect parts of the vacuum system, the car may have difficulting adjusting for an idle circumstance. I kno my 90 galant wouldn't start for a bit b/c we removed a line that i suppose was important, and it didn't compensate for it.
Not sure i've ever seen a car with a fixed throttle, that can't be adjusted though, Also, i might mention that these old-car gear heads will and can make any engine swap possible provided it's mounting the same direction. buddy of mine has a 5.3l Silverado engine in a 81 Buick with all kinds of custom adjustments. He gets 30mpg on the highway, which is sorely upsetting.

also i apologize for posting 2 weeks too late. been busy.