Brooksdesign64

2000 V6 3.8L 165K miles.
New plugs, plug wires, coil, PCM, MAS, and new fuel pump.

Starts and idles fine in the driveway (sounds good).
Drives fine when first going down the road, then when I accelerate off a stop there is no power, I will hear a backfire (pop) in the exhaust headers and the gas pedal can go to the floor and I will creep through the intersection at 3000 RPM and 5 mph. (dangerous in Dallas)

If I restart the engine, all is fine again until I need some heavier acceleration.
It will drive highway speeds, but it may take me 0-60 in 45 seconds.
If I stomp on it, I will hear a sucking sound from the throttle body.
Vacuum hoses all connected.
I cleaned the IAC and it helped a little bit but did not solve the issue.
It is not throwing any codes. (which is disturbing)

I am confused as to which direction to look.
Vacuum hose leak?
Fuel supply issue?
Electrical/fuel sensors?
Fuel Injectors?
Throttle body?

Anyone experience something similar? How did you fix the situation?
Any advice is greatly appreciated.

Derf00

You are most likely getting unmetered air into the intake. Any check engine light on?

Possibly a cracked manifold or bad intake seals. vacuum hoses can be connected but, are they holding vacuum or are they brittle and cracking?

Also, check your air intake hose for cracks/holes.

Brooksdesign64

Thanks for the response. Makes sense. That is a good direction to go because the extra air would make the air-fuel mixture lean and the MAS and computer can't adjust to air it can't measure. I will look at all the hoses tonight. I had fixed some leaks from brittle lines, but that does not mean there are not more lurking. Thanks again.

J.R. Floyd

my 99 mustang is doing the same thing need help think it's the cadlaconverter