W124 '94 E420 M119 Throttle Body/ Cruise/ Idle Help Needed

[whitleyone]

Hello to all. I recently purchased a '94 E420 with 60,xxx miles. The first month was great, and then trouble started.

I started the engine one morning and it hiccupped, ran very roughly, and then stalled out. I cranked it again and it started but stalled out again. On the third try it started and ran pretty much as normal. That afternoon the check engine light came on and it was having almost stalling episodes when first started. I took the car out to the MB dealership and they coded it to the MAF Sensor. I cursed a good bit but bit the bullet and bought a new unit and had it installed. When I picked up the car the service advisor said that there was a "soft code" for the TBA that wouldn't clear.

Sure enough that afternoon the check engine light was back on and the car was displaying the same symptoms. I should note that the cruise control also quit working with the second check engine episode. Anyway, the car would start and then the RPM's would dip super low and sometimes stall out. We bought a rebuilt TBA unit from Beckmann Technologies in NC (great service) and installed it, but did not have it immediately recoded at the dealership. Here is what it did. Upon start-up, the car idled about 500 to 700 rpm higher than it did previously, and when put in park the idle would cycle up and down about 300 rpm. When driving the car runs flawlessly but sometimes when letting off the gas you can feel the cycling for a couple of times and then it will settle down. The cruise still doesn't work. We took it out to the dealership to have the TBA coded, and they couldn't get the TBA trouble code to clear. They said to me that the rebuilt unit had to be bad.

I called Beckmann and they sent out a replacement unit with the warning that if the original replacement tested good that I would have to pay for the second rebuilt unit. You can probably see where this is going. We installed the second TBA this morning, went straight to the dealer to have it coded, only to have the same problem happen again. So it seems as if I will have spent close to two grand on parts by the end of this week with the car having the exact same problems as before.

Can anyone on this forum offer any advice as to what else could be causing such problems. The wiring harness has been replaced so I don't think that it is a factor in this case. We have an appointment with an independent mechanic on Monday who thinks they may be able to better diagnose the problem, but I do not have unlimited funds to try to solve a problem that should have been solved by what the dealer told me needed replacing.

Thank all of you for your knowledge and any insight you can give me or the mechanic who will be looking at it on Monday.