97 Ford f150 rough idles and dies

Ive been having a problem where the engine cranks and idles, sometimes rough, then I try to accelerate and the car shakes and accelerates very slowly with shaking. I replaced plugs coil and leads and fuel filter with no effect but put on a new egr valve and that fixed the problem for 2 months. The same thing happened again and I cleaned the evr solenoid and that fixed the problem for 1 month. Then the same thing happened while I was out and while limping home it fixed itself. Now a month later, the same thing happened, but when I got home and shut it off, the engine won’t idle properly (very rough) for 6-9 seconds then dies.

I don’t know what to check at this point. Thinking it may be vacuum related or possibly a fuel injector or magic gremlins at this point. Any help would be appreciated!

May we assume the check engine light is on?
If it is, what codes do you have? The numbers (p0300, p0507, etc.), please.
You might have a bad idle air control valve.
We need more information, please.

Yes, pulled the codes today:
P1747-Pressure Control Solenoid A Short Circuit
P0750/P0755-Shift solenoid A/B Malf
P0743-Torque Converter Clutch System Electric
P1537/P1538-Intake Manifold Runner Control Banks 1/2 Open
P0141-O2 Sensor Heater Malfunction Bank 1 Sensor 2
P0161-O2 Sensor Hearter Circuit Bank2 Sensor2
P1409-EVR Control Circuit
P0171/P0174-System too Lean Bank 1/2

The Truck starts now, but still having the same issues where the engine stumbles when the accelerator depressed too much. I can accelerate very slowly but not above that point, the engine will not shift either once i get up to speeds of 30-40mph.

This many codes makes me think it’s all related to a central issue, maybe a circuit problem? I’m not knowledgeable enough on how the systems work to know how all these problems would be connected.

Any Ideas?

You have to look at all the codes. None of them effect one system to another.

When there’s that many codes, and the engine doesn’t run right, the problem might be with the computer. Or the ECU.


Clear the codes
Reset the keep alive memory
Drive the car
See what codes are coming back

Are your battery and alternator up to the job?
Is the alternator providing a steady 13.5 - 15V at idle?

Do you hear any possible vacuum leaks?

Check out this website. The OBD2 theory part is free.

I think I would start with the P0171 and 174 codes. There could be a vacuum leak, but it can be an air leak anywhere past the MAF sensor. I would also recommend cleaning the MAF sensor with a spray MAF sensor cleaner ($6 from any parts store). Make sure the air duct is sealed to the throttle body. Then look for vacuum leaks.

Some of the other codes could be byproducts of these codes. The P0141 and 161 codes are separate and not related. They will have to be addressed eventually if you live where smog checks are required, otherwise they only affect emissions when the engine is cold. They should be fixed anyway.

I think I’d start with the O2 sensors. Those could affect driveability and the lean mixture problem. Ask your mechanic if there’s a way to configure the computer to run “open loop”. If this is possible, and the drivability problem gets better,fixing or replacing the O2 sensors should greatly improve if not eliminate the drivablity problems you are having. Ask yoru mechanic if the pressure control selenoid affect fuel rail pressure. If so, that’d be the next suspect for drivability problems.

It’s extremely difficult to sort out a problem over the internet in which multiple codes exist and for which I do not have a schematic.

My gut feeling is that you have at least 2 problems and one of them possibly related to a vacuum leak as keith suggests. If the truck were mine I would disconnect the vacuum plug at the fuel pressure regulator and attach a vacuum gauge. This would reveal in seconds if there’s a problem with vacuum.

As stated, I do not have a schematic for your particular vehicle but do have some for other 96 model Fords. In theory anyway, the layouts should be at least roughly similar.
Presssure solenoids, intake runners, O2 heaters etc, etc, show to have a common junction point related to the PCM so in theory (again, ha) this could point to a PCM fault or an issue with a power supply to the PCM. Whether your truck is like this I have not determined yet.

Whenever an electrical problem exists, the first thing I do is use a test light or VOM and check every single fuse or fusible link; both the in-cabin fuse blocks and the underhood one.
I’ll dig around in my junk some more and see if I can find a more relevant schematic and post back with something (hopefully) a bit more substantial than WAGing. :slight_smile:

Finally fixed the problem. It was a wire that burned through and was grounding out on the transmission wiring harness. Simple enough except having to remove the intake manifold to get behind the engine to access it!