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1988 911 Carrera Short Shifters and Intermittent Engine Running

Transmission and Clutch

Vehicle Information: Model: 911 Carrera; Year: 1988; Body Type: Coupe; Engine (type, size, modifications): 3.2L - Weltmeister Chip, Bored Throttle Body, B&B single inlet -dual outlet Muffler, Bursch Cat. bypass pipe; Total Mileage: 134,132;

1. Short Shift Kits. I have searched high & low for any reference to aShort Shift Kit for the 1987-1989 G-50 transmission without success. Doesthere exist such a kit for these model years? I reviewed Tech. Notes IIrecently and stumbled upon a reference to such a kit in a Bruce Andersonresponse, on a different subject, yet no p/n was mentioned. I have spokenwith the local Porsche Dealers without success. The only kit p/nreferenced is M241 production option.2. Intermittent Running Problems. Recently my car has developed anillness of yet to be determined origin. As is the case with electrical &fuel problems they are very difficult to distinguish one from the otherat times. The situation is as follows; approximately 3 months back whenthe ambient temperature reached 80 degrees or above, with the car fullyat operating temperature and a minimum of 25 miles had been driven theengine would begin to surge drastically. The Tach would jump from steady,approx. 3000 rpm at 60-65 mph, to 4000 rpm then drop to 800 rpm. A lossof power would also occur due to the surge and rpm fluctuation. At idlespeed of the engine would continue to increase & decrease. I would unplugthe Idle Circuit Switch on the throttle body, idle would stabilize toapproximately 1200 rpm and I could nurse it home. Using the shop manualsI began testing the fuel & ignition Systems. The results were a replacedIdle Volume Valve which appeared to resolve the problem only to now haveencountered a different one. While driving up the freeway, again engineparameters were at normal operating level, I experienced a sudden lose ofpower as if the fuel system was shut-off. I was able to travel to thenext available exit while scanning all gauges to identify any abnormalparameters. While the engine would lose power I never had a drop in rpmsas previously experienced with the surging stated previously. At astoplight on the exit ramp the engine remained at steady idle with nosigns of a problem. Upon acceleration the engine hesitated excessively tothe point where I had to feather the accelerator and clutch until thepower returned enough to engage first gear and continue. I went to thenearest parking lot for inspection of the engine for any & all visibleproblems. I was able to shift from first to second gear before enteringthe parking lot and all the while the engine was struggling to retainpower. When parked and engine idling there was no indication of aproblem. Idle was steady at 850 RPM with no surging, no visible intake orvacuum leaks. As I tested all hoses & connections while at idle itseemed that I found the problem as the engine suddenly increased rpm from850 to 2200. Believing I had discovered a vacuum leak in the intakesystem I shut down the engine and began a closer examination. Unfortunately I uncovered no such leak. I removed and examined all vacuumlines and intake manifold hoses for cracks, loose clamps, restriction, etcetera, spending the better part of 3 hours removing the majority of allthe hoses & lines for closer inspection. I replaced numerous clamps onthese lines and reviewed connections for accuracy. After I had completedthis effort the car started easily (as is normally the case), reviewedthe engine and connections and then returned home which was another 20miles away. During the trip home there was no sign nor indication of anyproblem and I had an uneventful trip. I am now reviewing thediagnostic/trouble-shooting portions of the service manuals under fuelInjection, ignition and electrical systems, identifying all componentswhose failure would manifest itself by affecting engine performance aspreviously described. Components tested to date:Air Flow Sensor (within parameters), Fuel Pump Power relay (replaced),Idle Circuit Micro Switch (within spec. and all defined settings for DragLink and throttle linkage tolerances accurate), Temperature Sensor II(within spec. over complete temp. range. Reference & Speed Sensors (Oscilloscope not available so could only measure resistance values -acceptable), Distributor Cap, Rotor, Spark Plugs & Wires replaced withinlast 2000 miles and tested (acceptable), Engine Compression - 175-180 psiacross all cylinders (however - indications of valve guide and sealsdegradation - cylinders 5 & 6). I have not at this point tested FuelPressure, Fuel pressure bleed-off, Injector spray patterns nor injectorpressure break levels to manufacturers specifications. I have also nottested the fuel pump to date, however it is planned soon. With the above information have you any suggestions or knowledge ofsimilar situations and their cause which may help me to isolate and solvethis gremlin of my Carrera? This car has been my daily driver for thepast 2 1/2 years come rain or shine. We have traveled over 40,000 milestogether over this period with nary a hiccup except maintenance.

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