My first issue started on the interstate. I had this odd shudder at constant speed every once in a while, with bursts every 5 seconds or so, which would come and go sometimes for many minutes before returning. Next I noticed hesitation on throttle and an unsteady idle. I checked codes and got 232 but that doesn't seem to tell me much as a few things could cause that code to be thrown. I pulled the vacuum line from the FPR which didn't change the idle so (going off of internet searches) I'm going to replace it. I cleaned and tested the IAC which seems to be working, but after doing this my idle changed from low and unsteady to very high (like 3000 rpm) but fairly steady. When I put it in gear it calms down a lot but probably still is at 1000-1500. Not a condition I really want to live with. So park and neutral have a really high idle, seems odd to be so much higher when not in gear. What might cause this? I also noticed that the harness for the crank speed sensor has some sheathing stripped back so I'm going to replace that, though I would not think this could be the entire issue. Any ideas?
Thanks,
Alex

 

Sounds similar to my issues (82 244DL/B21F/Manual); I've done a lot so far, (starting with cheapest); new fuel pump in-tank helped for a day or two, then problems came back -- very intermittent. Checking injectors today. (Sorry, didn't have a solution, but thought I'd let you know you're not the only one)

 

Have you checked for vacuum leaks? BIG ONES?

 

I have not found any vacuum leaks, but I haven't used a torch or anything, just inspected hoses. I got two TP sensors from a junk yard and swapped the better looking one in, which seemed to quiet down the idle for a while, later returning to previous symptoms. I also replaced intake air hose as mine had rips in it (which would cause problems but they weren't improved by replacing it). A friend has suggested it might be an O2 sensor, but I'd really like to know before dropping that kind of money. Given I had code 232, an O2 sensor seems like the next logical step. I did check injector pulse and all are getting appropriate voltage so I don't really expect an ecu issue, I think it's probably a sensor. I did notice sometimes at idle if I goose the throttle it will calm down, which led me to think of the TPS, but maybe stuck TB? Also does the IAC normally turn off above a certain rpm? I wonder if it is getting stuck open or getting signal to stay open too long/too far etc.

 

its an o2 sensor problem. Check the wiring to the sensor. When it rains outside and the o2 sensor gets wet on the wiring on my 740, it will throw those code along with others. Reset the computer by disconnecting the battery or use the method outlined here ( Engine and OBD Diagnostic Codes )to reset the computer. see if this takes care of the problem first. The computer doesn't like to drive properly with this code in its memory.