The most probable cause I know is that you need a new catalytic converter and /or oxygen sensor. It slows down especially when you go uphill on the freeway. The more you step on the gas, the more it slows down. There is too much excess gasoline going to the catalytic converter and gasoline is clogging it. The catalytic converter burns the excess gasoline and produces acceptable HC, NO, CO gas fumes out of the exhaust to prevent too much smog on the air. But if there is too much excess gasoline, defective catalytic converter cannot handle it, it then clogs up and there is no way for your exhaust gas to leave causing it to slow down.
The oxygen sensor purpose is to mix the correct amount of air and gas going to the engine. Usually there are two oxygen sensors for 4 cylinders. One on the exhaust manifold by the engine and the other one beneath the car after the catalytic converter.
Also, do you have the correct ignition timing around 10 degrees before top dead center at 650 RPM. And advances upto 22 degrees when you rev the gas around 1000+ RPM.
Is your check engine light ON, need to know the code. You can buy a $15 OBD 1 code reader at the Auto Parts Store (OBD 1 code reader for 1995 and below, OBD 2 scanner for 1996 and above). It should come with detailed simple instructions counting the blinking light on the dashboard. Count how many blinks, then it will pause for a few seconds, then blink again. Usually 1 blink, pause, then many blinks. (Example 1 blink, pause, followed by 5 blinks. It means Code 15. If there is NO check engine light, forget this part of checking the blinks.
Thursday, September 23rd, 2010 AT 6:11 PM