Van losing power esp on hills; sometimes jolts in/out of gear; start-up problems on 1997 Volkswagen EuroVan

Long running problems with severe loss of power, esp going up hill. We had several cylinders misfiring, so have just replaced all the ignition wires and the coil pack, which we thought would be the answer. Things have improved slightly but we still lose power going uphill once the car has warmed up. Sometimes it feels like it is jolting into gear. Once power is slipping away it is impossible to get many revs. Also, it is erratic when starting up in the morning, sometimes it cuts out a few times first. After replacing the wires and coil pack, we immediately got these codes on our ODBII scanner, for the first time - 17952 (P1544); 16505 (P0121); 00518 (P0121), which are all related to the throttle. We are confused as to why the current symptoms are similar - altho not as severe - as the symptoms we had before replacing the wires and coil pack, and yet we had not had these throttle codes on the scanner before. We are driving the van in Latin America, so it is not easy to get parts, nor to find mechanics who know anything about this model of VW. any tips hugely appreciated. thanks

by in Irvine, CA on March 28, 2013
2 answers 1 comment
ANSWER by on March 28, 2013
possible your throttle body is sticky. it may need to be cleaned(use recommended cleaner if possible). not sure what fuel is like there compared to north america. possible contamination. rec. clean fuel system if possible. ethanol treatment to 1 tank of premium. may also want to change fuel filter. the climate may have an effect on air intake also. recommend upgrade air filter to high air flow type such as K&N.
COMMENT by on March 28, 2013
thanks! We will look into these options. Fuel is undoubtedly of a poorer quality. We have recently changed the fuel filter, but not cleaned the fuel system or throttle body. cheers.
ANSWER by on March 28, 2013
seek diag it cold be several issues,we would just be guessing