2001 Ford Taurus

I have a 2001 Ford Taurus and have been having some weird issues with it. First it started with a chirping noise that was real faint at idle and couldn't be heard at all when driving. The first place I took it to, tried to tell me I needed a new serpentine belt and water pump. They told me the water pump was loose (which I grabbed onto it and it didn't wobble like they said it did). So I took it to the dealership and they told me I had a leak of some kind (I'll post back later with more details about what the problem was, but the documents are with the vehicle at the dealership right now).

Never had any problems before this. But after I got it back, on two separate occasions the vehicle would start, shake violently, then stall. This was after about a 20 minute drive, then I ran into a store for a few minutes, and came back out. After waiting for a while, the vehicle would start up like nothing was wrong. After the first time, I took it to the dealership and they told me it was the camshaft sensor, which was replaced. It acted up again about a month after the sensor was replaced.

I was going to make an appointment to bring it in, but then before I got the chance to take it back in, the other night after work it wouldn't start at all. It wouldn't fire. I had it towed into the dealership. This morning it started right up for them and they have been able to start it without a problem several times and have test driven it without any problems.

Any suggestions? Someone said it could be the Viper security/remote start system I have in the car.

Apparently the new layout doesn't let me edit my question. Anyway, I wanted to add that this last time I took it in, there was supposedly no error codes on the computer.

. Check for codes.

. Replace the spark plugs with the same Motorcraft plugs that came in the car, if they have not been changed in 50,000 miles. Ensure that each coil-on-plug's coil connector is installed squarely over the plug. This will prevent any misfires.

. Perform tests in the link below:

https://www.askmehelpdesk.com/cars-t...ml#post2123675

There are a host of big time helps for your car in the Sticky. I recommend that you only use SAE 5W-30 full synthetic engine oil. Additionally, change the transmission fluid and filter every 30,000 miles, using either Mobil 1 Multi-Vehicle Synthetic ATF or Amsoil Universal Synthetic ATF. I own a 2000 Taurus with the Duratec engine.

I'll try what I know how to do or am comfortable doing. I just had the fluids flushed when that leak was repaired. I told the dealership to keep it over night and keep testing it. Also from what I've read about the Viper security systems, if they do stop the vehicle from starting, it wouldn't crank at all as it seems that the safety mechanism that prevents one from starting the vehicle stops it there and won't do anything unless the system is active (which obviously I deactivate the security system when trying to start the vehicle and even tried using the remote start to start it, but that failed just the same as me starting it). Either way though, I may try putting the system into Valet mode just to eliminate it as a possibility.

I eventually had the fuel pump replaced and haven't had any issues at all with starting since then. But my gas mileage has gone from 26-30 MPG down to 12-16MPG.

The dealership told me that the reason is probably the fuel filter, which should be replaced after replacing the fuel pump (which I don't know why they wouldn't have told me that when they did the fuel pump). Anyway, the fuel filter was probably due to be changed anyway (been almost 50k miles since it was replaced). I just had it replaced earlier today, and that's why I'm posting back here.

Someone else mentioned to me that the poor gas mileage is probably due to the camshaft syncro replacement.

I would focus on:

. Engine Coolant Temperature (ECT) Sensors can radically affect gas mileage:

https://www.askmehelpdesk.com/cars-t...tml#post293582

. MAF Sensors--these can also affect gas mileage.