'96 Caravan Hesitates on Cold Days

[ecfune]

My '96 Grand Caravan with a 3.3L hesitates on cold days. As soon as the engine hits normal temperature, it runs fine. I had the code scanned and it says, engine misfire, egr system failure, possible camshaft sensor failure. The vehicle will run but will sputter (drop in rpm) and hesiates until the engine warms up and then everything is normal. I do not have this problem during the warm season. I have replaced the coolant temp sensor, egr valve and solenoid, and coil. The problem is still there. The service engine light is also lit. I checked for vacuum leaks and connections. It seems like it has something to do with the engine temperature or ambient temperature.

[jamesslcx]

ecfune, how many miles are on your van? What exactly are your codes? Have you used a fuel system cleaner regularly? No rips, tears or cracks in the ductwork leading to the air filter?

[jamesslcx]

Problem could be anything from o2 sensor to tps sensor etc. I assume you have stayed on top of maintenance well.

[ecfune]

James - Thank you for the quick reply. The van has about 177K on it. The last time I had the codes read, they are: P0401 (EGR system fault), P0300 (cylinder misfire), and P0340 cam sensor condition). I replaced the EGR valve and control solenoid, coolant temp sensor, check the plug wires, replaced the coil and the problem is still there. The dusctwork is OK and I did not see any vacuum leak. The problem happens first thing in the morning when the engine is cold. Once it is at normal operating temperature there is no problem. You can drive it all day with no problem. So what I do is to warm up the car for about 15 minutes and then drive off with no issue. If I am in ahurry and forgot to warm it up, the hesitation occurs while driving and goes away as soon as the engine is warmed up. I do not have this problem during the summer months. I'm confused.

[jamesslcx]

ecfune, hmmm, problem only happens in open loop conditions when sensors are not providing much input to computer, problem goes away in closed loop conditions... you seemed to have covered just about everything. Just a thought I wonder if it could be PCM related? Also have you checked your spark plugs lately?