Please help resolve a problem that started recently on my W124 230E with 280k on the clock. The car “coughs” and “sputters” badly after ten to twenty minutes driving; even worse when going uphill and the weather is hot. The car, when stationary (in Park mode) experienced an occasional sputter – rpm dips from 1k to about 0.5k for a split second. The problem is more prominent when in drive mode when at traffic lights or junctions with the A/C switched on. Under acceleration from between 10k to 20k rpm, the engine sputters very badly to the odd occasions where the car dies on the road. The car had problem restarting but after replacement of ICU, it can be restarted almost immediately.

Parts tested and replaced:
• EHA Valve initially unplugged but problem still occurs. Unit later replaced.
• ICU replaced due to starting problem.
• Fuel Pump Relay replaced and problem persisted.
• OVP contacts cleaned; 10amp fuse still intact.
• HT leads and distributor checked for connectivity; no problems detected.
• Fuel injectors replaced.

Mechanic suggested replacing the fuel pump but would appreciate advice from forum members. Have already spent a substantial amount of money on parts (and labour) and just need to confirm that replacing fuel pump will resolved this issue.