Random Limp Mode '97 Chrysler

1997 6 cylinder Chrysler Cirrus 162,000 miles

My car will randomly and unpredictably go into limp mode. I suddenly find myself in second gear while my engine is revving at high speed (3000-5000 RPMs) in order to maintain velocity. The check engine light comes on immediately, but usually switches off after 2-3 days maximum, and typically less than that. If I pull over, and turn off the engine, it re-sets, allowing me to start the car, and continue my journey, shifting normally.

Additional pertinent information:
• it happens more often when the weather is warm
• it has happened while traveling down the highway at 65 mph (scary!)
• at times, the shift into second is so abrupt, it feels as though I have been rear-ended
• once, while in a traffic jam and moving at about 20 mph, I hit a pot hole and the engine started revving at 3000, with no change of gears
• a couple of times, rather than throwing me into second, it has seemed to throw me into neutral, with the familiar high revs, but absolutely no power with increased pressure on the gas pedal
• it is happening with increased frequency i.e. I have had to stop as many as six times during an 16 mile trip.
• Recurring computer codes: P0140, P0141, P0700, P0765, P1494

04/2011 replace right front cam seal
Front engine mount
Replace front valve cover gasket w/tube seals
Front bank spark plugs & wires (3 platinum plugs)
Transmission flush

05/2011 cylinder #5 misfire
Replace rear valve cover gasket & tube seals
3 platinum plugs (leaky power steering pump fouled the plugs)

05/2011 recall work #C45 floor shifter ignition/park interlock
Push rod trans- shifter

09/2012 transmission shift solenoid

10/2012 6 new plugs & wires
Plenum gasket
Distributor cap
EGR valve gasket

There has been other service work done during this time period, but (I think) I have included only that which may relate to the transmission. I am so frustrated, and my mechanic is stumped. He has referred me to either a transmission shop, or a Chrysler dealer. After hearing my account of the problems over the phone, the head mechanic at the dealership suggested that it’s time for me to get a new car.

Any help you can provide will be greatly appreciated. Thank you!

The codes P0140 And P0141 indicates the O2 sensor isn’t working and requires replacement.

The code P0700 is Transmission Control Malfunction. And the code P0765 indicates Shift Solenoid D Malfunction. This could be caused from a malfunctioning transmission control solenoid pack.

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The code P1494 indicates the EVAP leak detection pump solenoid did not change status after the port solenoid was energized. This means there’s either a problem LDP solenoid or the wiring to the solenoid.

Tester

The mechanic feels that the P0140 & 0141 codes are unrelated to any transmission problems, & likely a result of the mix of today’s fuels.

The transmission shift solenoid was replaced in September, and did not correct the problem.

"there’s either a problem LDP solenoid or the wiring to the solenoid"
Is it possible for this to cause the problems I have described?