I have a 2003 Caravan SE, 2.4 dohc engine, auto trans. with 67k miles. It runs good except for a quirky problem, which started a few months ago. The engine misses as you accelerate through 40-45 mph. It starts good, and runs good at higher or lower speeds. As you approach 40 mph, there is a little roughness. By 40, it feeles like a dead clyinder, like a bad plug or wire. If you ease through to above 45, the shudder in not as bad. The harder you accelerate through 40-45, the more severe the miss is. Above 50 the engine is smooth and responsive. It will cruise nicely at 80 mph. What the hell?? Been fixing cars a long time and never ran into a problem just like this. Ocasionally, the check-engine lite comes on. The engine runs the same, lite or no lite. When I run an OBDII check, it shows "very minor vacuum leak", which I have not been able to find. I reset the lite and keep scratching my head. I suspect a bad TP or speed sensor, but don't want to just changing parts. There might be a dealer bulletin out, but dealers can be like quicksand. Is therer a site where the public can factory bulletins? Anybody got any ideas?
Thanks Guys, Great Site!!
Finbouy

 

As though something is effecting the working of the EGR valve. A small leak in the EGR would be hard to fine though the Vac line would not be. Have found small leaks using a propane torch. See if there is any change in idle using the torch around the EGR.
This would be a test of the EGR
Using a vac. brake bledder to pull Vac. on the EGR will cause the eng. to run rough or even die at idle. EGR should also hold vaccum.

 

hey thanks...I'll check it out!