Car starts, and idles, but won't accelerate

03 Lincoln lsv8 here, the car starts, idles, but won’t accelerate. When you hit the gas, most of the time it does nothing, but sometimes will go up to 900 rpms, then stall, it does the same thing in all gears. It will drive forward, but as I press on the gas, nothing. Read a lot of problems with the throttle body, so I replaced that, and the fuel filter after that. Still having the same issue.

Is the check engine light on? It sort of sounds like it is in limp mode. But if that’s the case, the check engine light should be on.

the check engine light is on, and I’m pulling quite a few codes.


I figured it was something to do with the fuel system, but with all these codes, where do I start.?

All those codes, none of which have anything to do with the throttle body. So you replace the throttle body. Did you even look up the codes? You could be right about it being a fuel problem. Those codes give you a clue as to where to start looking for the problem. I think you start with. The numerically lowest code.

Those codes all point to various electrical problems - shorts or opens. I’d start with the PCM. Strat with grounds. a bad ground is an open circuit and will give you lots of strange problems.

By any chance did you buy this recently for a really low price? There are lots of “flood cars” hitting the market from the hurricanes in Texas and Florida last year. THIS is the kind of problem that appears in flood cars.

Good Luck, I wouldn’t want to try tracing all that down!

TPS Throttle Position Sensor is where I’d look. May be tested with a simple ohmmeter.

I’d start w/the p0108. The engine won’t run well with a non-functioning MAP sensor. You can read more about it here, and research the other codes too if you want.

P0108 - MAP Pressure Circuit High Input

MAP means intake Manifold Absolute Pressure. It works just like a barometer, has a chamber inside with no air in it, a total vacuum. It measures the difference in pressure between that vacuum chamber and its pressure input, which is a big thick hose running from the intake manifold to the sensor. But instead of measuring the atmospheric pressure like a barometer does, it measures the air pressure in the intake manifold.

The computer reads the MAP sensor’s voltage constantly to adjust the amount of fuel to inject for that engine operating condition. A low voltage corresponds to a low pressure, and a high voltage corresponds to a high pressure. Except under a wide open throttle, the pressure should always be lower than atmospheric, and therefore a low voltage. You sensor is saying the intake manifold has a high pressure, close to atmospheric all the time. That’s not possible unless the throttle were stuck wide open. So you got one of these problems most likely

  • the MAP sensor vacuum chamber has sprung a leak, isn’t holding vacuum.
  • the pressure sensor inside the MAP sensor has failed
  • there’s a problem with the voltage reference to the MAP sensor
  • or a problem with the ground reference
  • or with the wiring between the MAP sensor and the computer

Until you get that resolved, the engine will never run correctly. Do you know how to check the ability of the MAP sensor to hold vacuum? That’s where I’d start if I had that problem.