Diagnostic scan tool

[baz]

Does anyone know if its possible for a diagnostic scan tool to show, NO CODES,even though your car seems to have a problem with the TPS or vacume, I have a CAN OBD11 MEMOSCAN.diagnostic tool. see rpms getting stuck

[Russ]

I don't think that would be unusual as vacuum leaks are more of a air / mechanical problem and will probably not show an error code, much like some fuel related issues won't show either. Unfortunately it may be a case of trial and error and searching for leaks that way, first thing I'd be doing is looking for hoses that may have come off or been left off when servicing :(

[ratter]

Many of the cheaper scan tools only check generic OBD2 codes, they do not check manufacturers codes, it is possible there are faults in the system that your scanner may not be reading, but it is also possible that a sensor can not be operating correctly and not give a code

[REDDYZ]

Cougars have OBD-II interface. However, it depends on the scan tool you are using. Unless that tool is specifically made for that make and model its really a tricky job to get codes out of cougar. I have used Snap-on and Launch tools. There are about 5 to 6 different options to get into the system. I mean by selecting Oz Ford, or Euro Ford, or Mercury or Mazda. Tricky part was most of them gives you simplified options with no codes and I remember only 1 or 2 gives you lot of diagnostic options, display live data and comes up with codes.

There is another possibility that you can look into. Since you mentioned in other thread that rpms are going high when you engage clutch, there is a possibility that throttle body is getting stuck at times. Check the throttle cable and butterfly operation and see if there is any build up in throttle body. You might think how can rpm go high if throttle is stuck. With manual cars say for example if are cruising at 3000rpm and throttle is stuck. Now when you press clutch you are taking load off the engine which will automatically increase engine rpm at the same throttle position. Hope you got my point. Its worth checking the butterfly and throttle cable operation.

[baz]

I did think about the throttle body because its only happened twice in about 12 months. I have got a PTS on its way from rockauto but might give the throttle body a clean. Any easy ways of doing the clean?