Hi, new guy hoping u all can help me out.
1999 Grand caravan, 3.3L flex fuel (vin code G). 187,000 miles.
Plugs and wires about 10,000 miles ago. Has been running like a champ. I do suspect an exhaust leak, but otherwise no problems. Yesterday it suddenly starts stumbling when accelerating like a carbureted engine would if an accelerator pump went bad. Seems to cruise okay, but also hesitates under acceleration and will occasionally backfire. I also notice when revving the engine in neutral it seems to want to hang at higher rpm before dropping back down to idle speed.
I checked the fuel pressure at the rail and the gauge reads 62psi. Researching online says should be 49-50psi. But everything I've seen online says this van is supposed to have a return type fuel system, but what's under the hood appears to be returnless. Were the gas and flex fuel engines given different type systems? What is the correct fuel pressure for the flex fuel returnless system? If 60 psi is in the range of normal, I'll probably start by throwing plugs and wire, and possibly a coil pack at it. It's cold as heck here so I thought I'd start by asking the questions before laying in the driveway guessing
Thanks
Jeff

 

These are usually signs of a cam or crank sensor dying. Yet the fuel presure seems too high. I don't think a flex fuel systen should be any higher than a regular return style system. I'd start with the CAM sensor from the dealer...not aftermarket.

 

I'd have a look at the throttle body to. Check the connection and maybe take the body off and clean it.

 

Hey all, just wanted to give an update on the fix. Decided after checking everything just to try the obvious and go with plugs, wires and coil first. Also pulled the upper intake to see if I could get a peek at the suspected exhaust leak.
visually everything looked fine when I removed it. Plugs looked just as I thought they should for 40,000 miles (more miles than I had thought)......

until the last plug out of the engine. The inner electrode had receded back all the way deep into the insulator. I snapped the insulator open and some how the inner resistor in the plug had pretty much vaporized and allowed the inner electrode tip to slide back about a quarter inch into the insulator. I've never seen or heard of this before, but a new set of platinums and its running like a champ.

 

That's a new new for me to. Thanks for the update.

 

Good find on the plugs, but with all the work to remove the upper manifold, seems like Iridium plugs might have been a better choice.