P0300, P0302, P0303, P0304

[newbluebeetle]

Recently we replaced the timing belt of my neighboor's car and we had a bit of a rough ride since. I noted that P0304 came back on engine check light. So yesterday I told him to pull it over my garage and I could look again. At this point I was convinced that the timing belt was off. So I open all the covers and I noted that the reference marks for the crank and cam was off by a tooth or so. So I align the crank and verified TDC. Then align the Cam to it's mark and installed it all back.
The performace increased and the rough ride dissapeared. It ran great. Later that night my neoghboor drove it around town for a while, then he got the check engine light flashing and the engine hessitated so in immedietly placed it in newtral, when the traffic light changed he placed it in drive and it work fine, however the chekc engine light when out, just to come back and stay on but the engine ran fine.
I got it today and recheck the position of the piston with relations to the crank and cam. all align perfect. also verified TDC and it was on the mark. Currently it runs fine. I took the battery cable and disconnected to reset the ECU and afterwards I'll connect everything and run it. I just wanted to know if anybody out there has enncountered anything like this or has any idea if I might be overlooking any thing else.

Thank you for your time to read this.

[newbluebeetle]

Just replaced the fuel filter and when i drainned the filter was nasty black junk. It felt like sand. When I asked my neighboor when was the last time he changed the fuel filter, he said that he never had. so I was looking at a 136,000 fuel filter. WOW That was a well built filter.
Hopefully that will take care of the multiple cylinders misfire.

[D2Beetle]

Well that is something to think about; I have only changed my fuel filter once and that was several years back. Perhaps it is time to change it again, almost 200,000+ miles later...