earlier this week i my had 2001 gt checked my a mechanic because it was throwing a few codes. a tune fixed the problem. i found out that the idiot who had the car before put 42lb fuel injectors in it. the car is currently tuned for them and runs perfectly. should i just leave the injectors on it since it runs perfect and not worry about it, or return it to the stock 19 lb injectors and get it tuned again?

 

Is your car supercharged?

 

42lbs injectors are OVERKILL for your car if it isn't s/c'd.

 

Detective senses tell me previous owner had a blower on there and pulled it off, leaving injectors and returned the stock tune

You can find 19/21lbs injectors dirt cheap, probably right here on this site.

 

Just leave them on there. If it runs good theres no sense in spending money for stock injectors and re-tune.

 

The car never had a blower. Would I get more power if I returned it to stock size? Before the tune they were causing it to run extremy rich

 

I'm with the other guys--I think it had a blower...

Nonetheless, while a tune can compensate for most of the issues the large/enormous injectors would create, fueling at lower loads and cruising speeds will be difficult to control likely resulting in fuel economy and driveability problems.

 

When I put my 42lb injectors on, before I loaded my tune on it, it would barely run. It started but filled the garage with smoke very quickly... nice thick black smoke I couldn't get it to rev past 1200 and it wouldn't start most of the time. Oh well, it was just a leak check.

When I dialed in my tune and increased my spark timing between 4-7 degrees across the board, I ended up getting 367 miles out of the next tank of gas... a good 35 miles better than I had ever done with the stock 21# injectors I had. There's no harm in leaving the bigger injectors on there. You're not losing any power, not losing any mileage, the shorter PW may be a little bit better in the end, anyway... just as long as the tune is dead on.

 

before the tune, it had 205 hp according to the dyno. (stock is supposed to be around 230) after the tune it was up to 233. my friend thinks that if i return it to the 19lb, and then get a tune, the hp will increase even more

 

If it's otherwise basically stock you're about right on. I really doubt you're going to see any power increases.

The cobra injectors have a different spray pattern, IIRC... dual-cone. At such short PW's though it won't matter, the fuel won't have the chance to hit the manifold runner walls... which is the only thing that could cause a problem. The dual-cone pattern will probably yield better atomization, anyway...