2000 Caravan shudders, pops, hesitates

[simpulman]

Hi everyone. 2000 Caravan 4-cyl w/130k miles. It starts up just fine and runs fine in idle but has the check engine light on. From a stop the engine runs REALLY rough and will stay rough unless I only lightly press the gas for acceleration, any harder and engine pops (like a backfire) and sputters. Check engine light will sometimes blink and will rarely turn off completely. In traffic if I try to pass the motor will hesitate to accelerate and shudder, but again a light depress of the pedal and will run relatively smooth. I'm not sure if it has a rotor to replace or points, wonder also if it may have something to do with exhaust/emissions. Hopefully I have not overloaded everyone with details and redundancy. Any help from you all out there would be so very much appreciated.

[Alphabravo]

You can start by going to an auto parts store to run a free OBDII scan to find out what the check engine light is trying to tell you and you can go from there. When it blinks, it usually means that the same problem is re-occuring.

[RIP]

Blinking SES light also means you're potentially killing the cat converter. Have it scanned asap.

[fredjacksonsan]

Have you ever had the timing belt replaced? A stretched timing belt/chain will cause what you are experiencing.

[simpulman]

Thanks, everyone. I haven't checked the timing chain but i will go to Advance for the diagnostic check and let everyone know what happens. Thanks again.

[Bear]

If you have condensation in your fuel tank she will act as you describe. Buy a bottle of dry gas, water out, HEET and put that in the tank and give it as try.

[simpulman]

Went to Advance and got hooked up to the diagnostic tool. The first problem is 'P0301-Cylinder Misfire Detected' which the guy said was probably a bad spark plug or plug wire. Bought those and will replace in the next couple days. The second problem was 'P0141-Oxygen Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)' which was a likely bad O2 sensor, probably the one away from the motor in the exhaust pipe. The sensor is a good bit more expensive but I plan to replace that in the next few days as well. I thank everyone for the great suggestions and I will post the results of these fixes soon.

[RIP]

http://www.obd-codes.com/p0141
http://www.obd-codes.com/p0301

[simpulman]

Wow! Amazing what a simple replace of plugs and wires will do. Runs smooth now just like it used to but i found something bad. First three plugs were slightly scorched or burned but on the last the end was coated in oil. What does this mean, not good I would guess. The check engine light is still on, the O2 sensor, but there are no effects on performance I can see. Anyone with any advice on the oil on the plug would be most appreciated.

[RIP]

Worn piston rings or scored cylinder walls. A compression check should show a reading below spec. Might get away with reboring the cylinder and replacing the rings with oversized rings. Worn valve guides or valve guide seals. Smoke at startup is an indication. Replace the guides and seals. A stuck PCV valve or plugged PCV tube. Change the PCV valve ($3) and check the tubing for any blockage. If you're short on bucks a hotter running spark plug may help for a short time. How often are you adding oil? Any visible smoke? SES light still blinking?

[fredjacksonsan]

Originally Posted by RIP

Worn piston rings or scored cylinder walls. A compression check should show a reading below spec. Might get away with reboring the cylinder and replacing the rings with oversized rings. Worn valve guides or valve guide seals. Smoke at startup is an indication. Replace the guides and seals. A stuck PCV valve or plugged PCV tube. Change the PCV valve ($3) and check the tubing for any blockage. If you're short on bucks a hotter running spark plug may help for a short time. How often are you adding oil? Any visible smoke? SES light still blinking?

All true; but if that plug was misfiring then it could have fouled. I'd drive it for about 5000 miles, pull it and see how it looks...