1993 Ford Thunderbird, acceleration issues..

First you need to dump the codes. Being a '93, it should be an EEC system-which allows a user to dump the diagnostic codes without a scanner. You need a piece of wire, a paperclip, piece of mig welding wire, anything that will conduct electricity. fordfuelinjection.com has the instructions how to do that. It's geared toward a Mustang but same principles apply...locations may be different though.

Just because the CEL (check engine lamp) is not on doesn't mean that nothing's wrong. The computer stores codes too for I believe 50 drive cycles. Might be 100. Many times dumping the codes will give a clue as to what's going on...I do it about once a month just to keep a watch on things.

2nd...keep in mind that a 3.8 isn't anything to write home about, especially in a heavy thunderbird. I think a 4 cylinder Mustang is faster. Well maybe not but it's a close race.

Mods...there's some things you can do, but the heads just don't flow much air so a head change is usually in order to open them up. 4.2 trucks and 3.9 Mustangs had dual port heads (split port) and intakes...they are the hot ticket for stock Essex performance. Then you're going to get into exhaust, intakes, blowers and turbos with the latter two being enough to blow the block to smitherines...or at least bust the crankshaft and lift the heads.

Surprised your current 3.8 hasn't lost a gasket yet. Impressive! 99% of them leak coolant into the engine with that many miles on them.

Welcome to the forums! These guys have it covered, and as you gather more info, we can help get more results. If you're serious about more power from your 'Bird, there are popular swaps that will net more performance per dollar and labor hour than twisting the nipples on the 3.8L. We can get this one going for a daily driver, and then you can analyze what direction you want to go for performance.

David

Head gaskets in rwd 3.8 is pretty common, about every 100k-120k. if your head gasket is going it most likely won't show up in the oil. I have had this happen 3 times on two different engines, it will start to use coolant. this will go on for a long time. If you drive it long enough it will end in a big puff of white smoke. No noticable loss of power untill they blow out. Never saw any evidence of water in the oil. Other than the head gasket thing they are great little engines. I have one with 260k, it has had two sets of head gaskets and a set of injectors other than that just small stuff and it still runs great. The little 3.8 is short on performance, If you really want more power you would be better off to buy a V8 car or a newer sixer (ie an 11 stang). With a mild V8 you could get twice the power and the same mileage of the 3.8. That being said, I did build a 3.8 mustang with some supersix stage II stuff. It ran pretty well and I used the smaller of their cam choices and my stock converter in the AODE. Also went to 3.45 gears. For reference if I had a manual trans and the next step up cam I could probably have kept up with a stock GT. In short getting HP out of the 3.8 expensive, but possable. If you have your heart set on building the 3.8 swap out your gears first, no less than 3.73s, or you will be dissapointed. Especialy with the stage III stuff.