I have a 1995 Ford Escort 1.9 motor, and the fourth valve seat dropped. I had the engine completely rebuilt. The car still ran badly and had a pinging/knocking sound, and then the timing belt broke. The engine shop replaced the broken timing belt. Then I discovered motor oil was blowing into the air filter. An engine mechanic tore the engine apart and discovered the new seals had deteriorated and were allowing oil into all kinds of parts on the car and burning oil, even though the car wasn't smoking. He re-built the engine again with a new ring kit a second time. These are still the symptoms:
1. Pinging/rattling sound upon acceleration, especially bad uphill. (sounds like a diesel truck)
2. No power uphill, car really struggles.
3. Horrible gas mileage (I used to get 37-40 mpg, but now only get 23-26 mpg).
4. Car shakes and struggles to stay on when I turn on the A/c.
5. Rough idle, especially when the fan comes on, acts like it wants to stall when both the fan and A/C are on.
I have had this car to three Ford service centers and multiple mechanics. There are no codes to read, and no check engine light is coming on. The idle perks up in park or neutral, but the car shakes and runs poorly in drive.
These are the parts I have changed on the car since the engine was rebuilt: EGR valve, oxygen sensor, battery, alternator/regulator, PCV valve, idle air control valve. I have had the catalytic converter checked for back pressure, and it is ok. I have used fuel cleaners and higher octane gasoline. Could the problem be a bad throttle position sensor? Nobody has been able to figure this car out. Do you have any ideas? Please help.