Ok here it goes,
I have a 1993 Toyota Corolla, 1.8 L, 4 cyl engine. It has 201,000 miles. The transmission is automatic.
This weekend I decided to give the car its over due timing belt. Everything appeared to go well. While I was at it, I gave the car a tune up as well.
When I first tried to start the car, it would not turn over. After pumping the gas and tinkering with the distributor, it finally started. However now the car idles very poorly. Here are the symptoms:
1) It idles very low...2) ...which appears to make the engine (and car) vibrate.
I have conducted some research into this, and the apparent reason is that the timing is off. However, I am very confident this is not the case. I justify this because:
1) The timing marks were aligned perfectly before reassembly. (even after rotating the engine several times.) 2) I was able to successfully set the timing to 10 degrees BTDC. 3) Once the care is moving, it runs very well and smooth - has lots of power.But here's the kicker...
The reason I know its not the timing, is because the instructions call for two connectors on the diagnosis port to be shorted together before checking the timing. Once I do that, the car idles wonderfully for about 5 seconds, then goes back to poor idle.
When I make the connection between the two connectors, there sounds like a vacuum is actuated within the intake manifold (specifically, the section before it branches out to the four cylinders.)
It's not the new wires, cap and rotor either...I tried putting the old parts back on to no avail.
I've checked the vacuum hoses, they all seem ok.
This is an unbelievably frustrating situation. If anyone has insight into the problem, I would greatly appreciate it.
Thank you,
Tom