I'm looking for some advice on the possible cause for this. A little history first, I bought this 1994 Cooper SPi back in December, it was an MOT failure on emissions (among other things). The 30 mile drive home was awful, the car was underpowered but it made it.
This is my first SPi so I did a lot of research and found faults with the PTC heater, Lambda sensor heater relay, wiring issues to air temp temp sensor as well cooling fan issues.
I have replaced all the failed components including a new Bosch Lambda sensor, spark plugs, leads and vacuum hoses and I'm getting no faults on the Rover MEMS app and everything appears to be fine.
The car started in the morning and the idle was a bit erratic, it was a bit jumpy driving around the block but once it had warmed up it settled down. I took it on a short drive and everything was fine. When I got back home I turned it off and had some lunch. I then went to take it for an emissions test at a local garage (pre MOT) and it wouldn't start, it turned over but just wouldn't fire. After what seemed like forever and lots of short bursts of cranking it tried to start, a few more attempts and a bit of throttle and it came to life. Again, the drive was a bit jumpy at first but it settled down and I was able to do the short drive to the garage. I told the mechanic not to turn it off and it stayed idling for a good 20 minutes while the emission test was carried out. Once back home I turned it off and immediately tried to restart it and it had the same problem.
I've asked this same question on a Facebook group and while I'm sure they mean well the majority of responses just recommended changing parts to see if that cures it. One part that came up a lot was the Crankshaft Position Sensor, but it was my understanding that if this is bad then the engine wouldn't run well at all?
Sorry for the long post but I think it's vital to fully explain yourself when asking for help diagnosing odd problems.
PS. It failed the basic emission test but passed the second test which was a bit of fluke because the garage couldn't match the engine and said it came back on his computer as not having a CAT when it does :)