92 Euro Stalling with Speedo/RPM Problems

My Euro has only 30,000 miles and here is the problem.While going to another town with Cruise on the speedometer would go to zero and surge back, occasionally the car would shudder a bit as if to stall, but it made it. When I slowed down in town it acted normally. When doen I started through town again to the highway, it started stalling whenever I took my foot off the gas. The Engine Service Soon light comes on, but the radio stays on as do fans and lights. You can instantly restart, but you must get and keep rpm over 1000 and maintain it while putting in gear to start out. I got back on the highway thinking I could limp home without using cruise and I made it with these symptons:the speedometer went dead and the rpm held at about 3000. Occasionally the speedometer would come back on, the rpm would normallize in the 2000 range and the service light would go off. Then the vehicle would shutter, the rpm would flutter but stabilize at 3000 and the speedo would drop off. For the longest time the speedo actually dropped right down, like a limp noodle. I pulled the codes using a paper clip and got 33 for MAP and 35 for idle. Since I pulled the codes I cleaned the IAC and topped up the tank. Now the codes read 12 only for normal and today I tried every stop and start and turn off/turn on trick and it stalled only once when starting and once at a light. Late this afternoon it ran normally for 10 miles in start and stop traffic. I am quite uncomfortable driving it out of town and do not want to start replacing everything that "it could be". I read well and understand well, but am not a mechanic of any sorts. Any ideas?

Sounds like we have a similar problem. Cleaning the air intake did me the most good. People told me the catalytic converter was bad but that wasn't it either. I'm beginning to suspect it is the prom or mem/cal chip. I did get that error code once but only once. Otherwise it seldom gives me an error code and never the same one twice. I do notice that the speedometer goes in and out, mostly out, so I suspect it is an electrical problem. Depending upon the price of the prom or mem/cal, I may simply buy a salvaged ECM and replace it. Last time I did that it was $50 for my van and it wasn't even the problem. The salvage yard even let me return it. Good folks. Will let you know if I get a solution. 1992 Sedan, 3.1, 138,000 miles.

So far I've replaced the Ignition Module, put on a new Cat. & muffler, new plugs, and cleaned the air intake.

I bought a used ECM at a salvage yard for $50, put it in and that solved my idling and speedometer problem. It was not the Mem-Cal or Prom chip that was bad but the ECM itself. I know that because they sold me the wrong ECM for my car (perhaps it was from a van or a Euro or something) so it ran rough and the speedometer was working but not calibrated properly. I switched the chip from my old one to the new one and that did the trick.

Thanks for the insight. I have a 93 euro w/140,000 miles. The car idles around 2,500 rpm and when driving the speedometer will stop working when the cruise is set. I've replaced the ICV and cleaned the intake and that helped some, so next I'll replace the ECM.

I discovered that a new computer was only $79 with the return of the old one.