1988 C1500 2wd w/350 rough idel, power loss, shuts off at stops.

Ok so I just bought this truck from my tinkering grand father and I have already tried to replace the MAP sensor and that didn't work. He had an after market filter system on it and I went back to the stock TBI setup. Like I said in the title. From a dead stop if you hit the gas in bogs down real bad and then finally starts moving like its got a 1.4L under the hood. Some times if will run ok but never like it did two years ago. He has replaced the injectors but it was quite a while ago. The check engine light comes on every now and then but doesn't stick around. BTW its got a TB spacer on it and I am think about getting rid of it. Ill take any good ideas. I messed around with the dang thing for about a week and cant seem to get it.  

I think my next stop in an O2 sensor. I was looking for it just a minute ago and couldn't seem to locate it. I thought it just be under the passenger side in the exhaust? Didn't see it though.  

what codes did you get ??????     have you got a friend with a scan tool that will plug into the OBD1 system used on that model...  you can read live data with that system...    you can also jump the A and B terminal on the aldl connector under the dash.. turn the key on and read the codes as the check engine light flashes...

do you have a 192F thermostat..?????  i have had the coolant temp sensor wires on some of those go bad.. installing a new coolant temp sensor pigtail with a new coolant temp sensor sometimes helps..    when the connector goes bad... the computer will think the motor is at -20F

where is the timing set at???
you have to unplug the proper connector described on the emissions sticker on the core support...  tan wire.. with a single black connector sticking out of the harness near the firewall .. or inside the cab , passenger side, above the passengers toe area...  sticking out of the ecm harness that passes through the wall there...  usually set at 15 before top dead center...

can you take a look around the motor...    see if you can see where the computer harness is grounded to the motor... make sure that it is tight... and the ring terminals are not broken off the ends of the wires...     remember.. the computer system only grounds through the connections to the engine block...


one more thing...  got a vacuum gauge...   hook it to the intake manifold..... start the motor... slowly increase the speed...  watch the vacuum.. it should stay steady...  if it decreases... you may have a clogged cat...  i just had a friend with a crossfire vette... would not get out of its own way...   the cat was completely clogged... i bolted in a new replacement...  what a difference...   you can for testing.. pull an oxygen sensor... see if the power comes back as that will allow the exhaust to escape... just for testing.. do not try to drive it with the oxygen sensor out...  it will shoot out flame and set things on fire if you test for more that a few moments...  

Ok these are all great ideas. Just one thing. The engine for some reason isn't throwing a code to keep the engine light on? Why and with out it staying steady can I still get the code read out?  

Oh and on the topic of the cat being backed up. Its funny you say that because right when all this started to happen I got an exhaust leak also???  

So it was a bad spark plug wire. Now it runs like new. However. It still stalls almost every time I come to a stop... I don't get it. Could this be caused by a bad break booster because I know it needs one.  

Have you checked the throttle position sensor? The computers in those trucks are "dinsoaur" type computers, you can shut the truck off, let it sit for a mintue, then start it back up and the check engine light will stay off for a bit then come on when it detects a problem again. I've got a '92 Silverado, and have had similar problems, from a bad TPS sensor.

Try pulling the toruble codes and see what you get.  

Just a thought, If you know of a competent shop, have them diagnose your problem and with their experience and high tech diagnostic tools, locate the defect, quote a repair price, then you pay the diagnostic charge (probably $125 or more) and buy the parts yourself (anywhere) and complete the repair. This worked for me when the shop discovered my distributor shaft and bushing was worn enough to cause a high dwell discrepancy in the electronic module which stalled the vehicle at every stoplight. I replaced the housing/shaft and viola! Unfortunately I bought two modules and lots of other parts before I had the diagnostic performed. Trying new parts blindly is a shoot in the dark method of shade tree repair unless you feel lucky.