420SEL (W126) hesitating, stumbling - help!
Hey guys, trying to help my Mom diagnose the issues with her new (to her) car. Here's her description of what's going on:
"It hesitates or jerks when I try to accelerate - like the power momentarily cuts out. Pretty random except on freeway driving-it doesn't do it at all (IF I haven't had to stop several times first). The slowing down and stopping a lot really seems to kick it in.
Idling is very rough - sometimes the whole car vibrates-you can see it shaking (if I idle very long it ALWAYS starts acting up). It does it especially when I accelerate - a whole bunch going up a hill."
I've been in it when it shakes at idle, but it always went away shortly thereafter - never been there for the worse performance described above. The car is an '89 with only has 45k mi on it (gorgeous!), so I started the 60k tune-up regimen early thinking perhaps under-use was the culprit. It now commutes at least 40 miles a day, so infrequent driving is not the issue.
Fuel filter's been replaced as have the plugs, cap, and rotor. Fuel additives seem to help for a short while, as have all the items mentioned above. I replaced the Cap and Rotor last week - car was totally fine until just a day or two ago....any ideas? hmmm reading the symptons again almost sounds like some debris occasionally clogging the fuel tank screen or something, but since that's normally a diesel-trait from algae, etc, I hadn't considered that...
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