Chrysler Repair: 98 Dodge Grand Caravan Sport 3.3L Misfire underload, actron obd ii autoscanner, grand caravan sport

Question
Hi Roland, I have read some of your other post and hope that you can help? I have recently bought a 98 caravan w/ 3.3L motor it has 200+k and I did somewhat of a tune up on it. Injection cleaning, new plugs and wires with ing. coil and pcv valve. When I bought it the speed sensors were bad so they were replaced 1st. I am having a problem with misfire about 3000-3500 rpm most of the time going uphill. and occationally trans dropping back down into 1st and won't come out until restart. The codes I have are off a Actron OBD II autoscanner and they are as follows; P1776 Manufacturer Contrl Transmission, P0300 Random/Multiple cylinder misfire, P0700 Trans contrl sys Malfunction, P1391 Manufacturer contrl Ignition sys or misfire,P0302 cylinder 2 misfire,P0303 cylinder 3 MF, P0304 #4 MF & P0306 #6 MF. The Freeze data = DTC that caused freeze frame P0300 Engine RPM 3168 Load value 62.3% MAP sensor 90KPA Coolent temp 102 Short term fuel Trim1 0.0% Long term Trim1 0.0% Long term Trim3 -100.6% Vehicle speed 48mph Fuel system 1 open1 fuel system 2 N/A  So that is all the codes I have come up with I did try and spray contact clearner around the EGR and other vacume areas to no avale, If I am not driving far or up a decent grade it doesn't do it, but if I am it seems to get worse the farther I drive then the Trans codes go and and it starts to act up. Otherwise it is a great van..LOL Thank you... Scott

Answer
Hi Scott,
The most diagnostic of the engine codes is the 1391 which says that the cam or crank position sensor signal is intemittently lost. That is not necessarily a failure of either sensor but could be either is not positioned at the proper distance from the surface which it is supposed to sense. It could also be an electrical connection of any of the 6 sensor wires (3 on each sensor), damaged cam magnet or crank pulse ring surface, loose connector, or failing sensor or  pcm, but my thought would be to buy paper spacers for the sensors at a dealer parts counter, remove each sensor and gently clean off the old spacer, put on a new spacer, and re-install with the tips of each sensor pushed in contact with the surface it detects (tighten crank bolt to 105 inch-pounds, cam sensor to 125 inch-pounds, while holding in contact). Cam sensor has a rubber o-ring so you may have to gently rock/lever it out its hole, and put oil on o-ring when you put it back. There is a hole in the flange near the crank pulley that will allow you to insert a socket/extension so that you can use a ratchet to remove the bolt on the cam sensor for its removal. The crank sensor is on the firewall side of the engine at the seam between the engine and the trans, on the back side of casting, just above the transaxle top surface. The cam is mounted in the timing cade cover near the thermostat housing. That is a minimal cost first thing to try. Of course there are many possible engine misfire causes that can either be electrical or engine mechanical but start with the sensors. If that doesn't correct it my inclination would be to do a compression check on the cylinders to get an overall indication of the mechanicals.
On the transmission, the 1776 is about the solenoid switch valve (low-reverse) apparently hanging up. You can remove the valve body from the trans from underneath (removing the pan and thus draining the transfluid) which would be the place to start on that one as well. Possibly it is just dirty, or needs replacement.
Then go further into these issues as needed. But because the trans seems to get into trouble when the engine is missing, try to deal with the engine before the trans.
Roland