Slo-pony

Hello All, new user here.
I've got an '88 GT 5.0 ragtop, found it in a feild. It's been trashed, and the block was cracked. I bought a short block out of a mid 90's Ford/Merc SUV, put the stock heads and intake on, a B303 cam, new lifters, timing chain and gears, valve springs and lockers. new MAF, EGR, IAC, TPS, O2's, temp sensor, cap and rotor, plugs and wires, headers, and flowmaster cat back system. I was hoping to just have that cool "lopey" hot rod idle, and the power of an H.O. Instead, it has a pretty variable idle, anywhere from 800 to 1300. Trying to hold a steady speed, the car kind of jumps or stutters. And, it just doesn't have the power I think it should. Please help, any ideas are more than welcome. If there is anything else I can describe, just let me know. I'm pretty new to this game!

saleenpride1986

Make sure the TPS is set at the right voltage, having it too high or too low can cause a spiratic idle. Make sure the MAF is clean, as well as the throttle body, and even the EGR plate it needed, generally not though. Is the car well grounded? are there any wires barely making connections or meeting groundings? Also, one of my past experiences on something my idle did a while back was that my ECU inside the computer casing was not 100% fitted properly, and cause my idle to be fine at some times, then mega high randomly, then jump 300 rpm lower than normal. Check those and maybe you will find it!

Another thing is perhaps the MAF is not calibrated properly therefore the computer is thinking more or less air is coming in than what is actually coming through!

93 LX FiveO

what kind of ECU is in the car?

88 is not a factory MAF car, make sure your wiring and injector calibration is correct.

Project 5.GO!

Good suggestions, everyone... But why has nobody asked why he would be fixing a car that he found in a field? I'm assuming his name is not on the title, so... Maybe I'm just weird, but if I found a car in a field, I certainly wouldn't be putting my time and energy into fixing it without finding the owner and having a title first. Anyone else find their car in a field, or in the middle of a tropical rain forest, or at the bottom of a lake?

Five0hFox

Have you checked for vacuum leaks?

gil4x4

Must be that new advanced auto parts commercial inspiring people.

As for why the car isn't running so good, assuming all the wiring and harnesses are good, I would try to hook up a code reader.

Slo-pony

I changed the ground, no difference. The check engine light isn't on. It shut off after I put all the new sensors in it. It is a stock MAF car, so I'm pretty sure the wiring is correct. Everything I've read says that 88 models that came from California had the MAF in 1988. I started out with an F303 cam, but that proved to be too much, according to Ford Motorsport, so I put the B303 in, the tech told me I wouldn't need any other modifications. Yes, I have the title. It was my uncles car he bought new. I found it in his field, traded him a pellet stove for it. I'll have to check again for vacuum leaks. I'll also check the TPS voltage. Would it need to be adjusted out of the box? I'm not sure about the ECU.....yep, I'm new. What is that? How do I check? I really appreciate all the help. I know this car will move, just gotta figure out what's wrong. I haven't replaced the injectors, just the O rings.
Thanks again!