I'm here looking for a favor from an E300 owner in the Washington, DC metro area (or surrounding suburbs).
I believe my throttle position sensor is bad. I have light hesitation & surging while cruising on the highway at a constant speed. City driving I have no issue. If I floor it, it accelerates nicely without issue. If I take my foot off the pedal, it slows down without issue. If I continually vary the amount of throttle, I have no issue. It only hesitates / surges when cruising on the highway at a steady constant speed.
I have a CEL with the throttle position sensor code. I understand this code can also be thrown by vacuum leaks, faulty intake manifold flaps, vacuum control valve, and other associated parts. The thing is - in trying to troubleshoot this, I've already replaced almost all of these parts, including all the vacuum hoses, cleaned / lubed the flaps, etc.
I can't find a used TPS *anywhere*, and a brand new one is nearly $500.
It's specific to the E300 diesel (E320 gas tps has a different p/n). I think it's also specific to the '96-'97 diesel, so one from a '98-'99 turbodiesel probably is a different p/n.
Before plunking the cash on a new one, I'd like to swap in a known-good one and go for a 10 minute test drive. That will tell me immediately if this is indeed the source of my CEL. I really really REALLY don't want to drop $500 on one of these only to find out it doesn't fix my issue. Being an electrical component, it's non-returnable if I buy one from the dealer and find out it doesn't solve my problem.
The TPS is right there near the hinge when you open the hood, on the driver's side. Very simple 5 minute job to swap it out. If anyone here that's within an hour or two drive from DC would be willing to spare a few minutes of time to do this, I'd gladly show my appreciation by buying you a full tank of fuel.
Thanks in advance!