Possible Damage from a Broken Timing Belt:
* Bent Valves: This is the most common problem. When the timing belt breaks, the pistons can collide with the valves, bending or breaking them.
* Damaged Piston(s): Less common but possible, especially if the damage was severe.
* Damaged Cylinder Head: A bent valve can damage the cylinder head.
* Broken or damaged crankshaft: Less common than bent valves
* Timing Chain Tensioner (if applicable): Some engines use a timing chain and tensioner. Failure here may have caused the skipping
Troubleshooting Steps:
1. Compression Test: This is the most crucial step. A compression test will tell you if each cylinder is getting proper compression. Low compression in one or more cylinders points to valve damage or a damaged piston. You'll need a compression tester to perform this.
2. Leakdown Test: If a compression test shows low compression, a leakdown test will pinpoint *where* the compression is leaking (valves, piston rings, head gasket).
3. Visual Inspection: If you have mechanical skills and are comfortable working on engines, carefully inspect the valve train (after removing the valve cover) for bent valves. Look for obvious damage.
4. Cylinder Head Removal (Possibly): If the compression and leakdown tests indicate valve damage, you'll likely need to remove the cylinder head to repair or replace the bent valves. This is a significant undertaking requiring experience and specialized tools.
5. Check for other issues: Even without timing belt damage, the following can cause misfires:
* Spark Plugs: Check for wear, fouling, or damage.
* Spark Plug Wires: Inspect for cracks, damage, or loose connections.
* Ignition Coil: A faulty ignition coil can cause misfires in one or more cylinders.
* Crankshaft Position Sensor (CKP Sensor): This sensor is critical for timing. A faulty CKP sensor can cause all sorts of running issues.
* Mass Air Flow (MAF) Sensor: A dirty or faulty MAF sensor affects the air-fuel mixture.
What to Do Now:
* Don't drive the car extensively. Continuing to drive with significant engine damage will likely cause further problems.
* Compression Test: Perform this test first. It's the quickest way to determine the extent of the damage.
* Seek professional help: Unless you have significant experience working on engines, it's highly recommended to take the car to a qualified mechanic. Repairing valve damage is complex and requires expertise. The cost of fixing the problem may exceed the value of the vehicle depending on the damage.
The skipping and missing at idle strongly suggest internal engine damage caused by the broken timing belt. A compression test will give you the necessary information to proceed. Be prepared for significant repair costs or the possibility that the engine needs to be rebuilt or replaced.
