The Chrysler Minivan Fan Club Forums banner

1996 Town & Country Dies on the Highway.

4K views 7 replies 4 participants last post by  Flavife 
#1 ·
Hi, I'm a new guy to this forum and I need some help. This van has a 3.8 liter engine and has died three times in the past month. This does not happen in town, with frequent shopping stops, only on the freeway after 15-20 minutes at speed. The trouble code shows P0300 for multiple random misfires. After it sets awhile the van will start and run great until you get 15-20 minutes on the freeway. I replaced the cam and crank sensors as they are common to all cylinders and where cheap, but the problem is still there. I static checked the coil and it tests good. Fuel pressure is 49psi at idle. There are no indications of excess heat, frayed wires, or poor connections anywhere. I'm stuck. Any thoughts out there? Thanks
 
#2 ·
How many miles on your van? Given it's age, Im thinking that if it's anywhere over 200,000 miles I might be inclined to think fuel filter/fuel pump.
 
#4 ·
The problem is that at idle there really isn't all that much fuel being delivered to the engine, however, on the highway your pump/filter (I'd go filter first) may not be able to keep up with the higher fuel demand.
 
#6 ·
I'm probably over thinking this because I can't actually replace any parts tright now, but there are a couple things that bother me. If the fuel pump is weak, why does it take 15-20 minutes on the freeway to show up? Would it not start to fail as soon as the load was applied? Why would the problem go away after the van sits awhile and run noramlly until getting on the freeway again(sometimes days)? Also, since I get the multiple random misfire code, isn't the computer reading a lack of spark? How would it know of a misfire if spark was present? I have seen coils fail when warmed up and then work fine after cool down, so I'm torn between the two choices. Is there anything I can check to help narrow this down? Anyone have any insights or other advice?
 
#7 · (Edited)
A trick. Barrow your wifes hair dryer (good luck), start it up and heat up the coil. If it starts "misfiring" cool it off. Go back and forth with it to confirm. I've never tried this but, who knows, maybe it will reveal something. In regards to the pump, same issue - heat. I agree. Tough call.

For most of my 26 years in the Air Force I worked avionics systems on jets. There was many a time when all you could do was surmise what was creating a particular problem especially if it was intermittent. You took an educated guess and hoped it fixed it. Once it was fixed taking the time to disect a component with whatever methods available was a luxury few took the time to do. Many times it took engineers with degrees out the wazoo weeks to determine the cause, if then. My point? Sometimes you have no choice but to take your best guess.
 
#8 ·
Some thoughts regarding the issue. The misfire can be caused by too lean a fuel mixture. Is the length of city driving long enough to warm up the engine as much as the highway driving, if yes that would tend to eliminate an electrical misfire from a coil. I have had several vehicles in the past that worked fine in the city but after being on the highway for a while or travelling fast would die and after some time would start up and run fine until the next highway trip. In all cases it was a lack of fuel delivery. The problem with the 1963 beetle was a swollen rubber gasket on the gas tank where the fuel/reserve level fastened to the gas tank. On the 1974 Pinto it was too long a rubber hose from the metal fuel pipe on the body frame to the mechanical fuel pump on the engine (the loop sagged so much it kinked the hose and restricted fuel. The fix was to cut 2 inches off the hose length). I suspect Shipo is right about fuel delivery and as a starter try leaving the gas cap off and drive on the highway if you have a scantool. If it does not die and only gives the MIL light (because gas cap is off) then troubleshoot the air system to the feul tank otherwise you need to check volume flow besides fuel pressure.

Let us know the final fix

Frank
99 DGC Sport 120650 mi
07 T&C SWB 8500 mi
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top