Ok.Check for vacuum leaks.A vacuum leak will cause the o2 sensors to read lean which will trigger the ecu to richen the fuel mixture,causing obnoxious fumes at the tailpipes & possible driveability issues.The purge valve and carbon canister hoses are known to dryrot & cause vacuum leaks and since the map sensor is probably the #1 or #2 most important sensor on a SD car,check it thoroughly.Make sure the canister purge valve isnt stuck open too,because it will cause an unmetered (rich) fuel condition. Just disconnect its vacuum hose on the intake side of the purge valve,plug the hose and see if it runs any better.Next,to make sure the egr system isnt causing your problem,remove the vacuum hose from the egr valve,plug the hose and see how it runs.If it runs better,troubleshoot the egr system.Anytime a code is present for a egr component,the ecu deletes/bypasses its operation in the ecu logic & it disables its function so that the ecu can run normal fuel and timing values,which are normally adjusted to compensate for the gases anytime the egr valve is open.However,if the egr valve is stuck open because of alot of carbon buildup or a defective evr solenoid, egr gases will still be allowed to pass into the engine and without the ecu compensating for these gases,driveability issues will likely occur.Next test,If youve got a multimeter,disconnect the harness from the ect sensor & touch a meter lead to each terminal on the ect sensor.Test it cold then warm the engine up and test it hot.The ohms value should match the chart below for the given temp listed.If the values are off,go ahead & replace the ect sensor.Reconnect the harness when testing is done.Next test,start the car up and let it run.Pull the vacuum hose off the fuel pressure regulator and see if fuel is seeping out of the regulator port or if the vacuum hose is wet with fuel.If either condition is present,replace the regulator.Next test fuel pressure.Autozone rents test kits for a refundable deposit or you can buy a gauge to permanently mount or you can use a tire pressure gauge,but it may not be 100% accurate.The Schrader valve (test port) is located on the stainless fuel line section a few inches from where the line connects to the fuel rail near the passenger valve cover.Pressure should be:
Key on/engine off= 35-45psi
Key on/engine running= 30-40psi
It also wouldn't hurt to pull KOEO/KOER codes.If you dont have a scanner,use a jumper wire/paperclip and a test light,since the 86-88 models dont have a check engine light.The diagnostic port is at the driver strut tower/firewall.The following link will help.The second white diagram you come to at the site in the following link shows you where to connect the jumper wire and test light.The test light will flash the codes out for you.The test directions and code list is also there.For each code set you get (if any) each set of codes will be flashed twice (OD & CM) If codes arent present,you should get code 11 (system passed code) Post any codes you get.Do the cylinder balance test afterwards.It will help you id any suspect injectors.
If none of the tests above fail,leaking, buldging or eroded posts on any/all of the 3 blue capacitors on the ecu circuit board and/or a damaged trace on the board can also cause your symptoms,but do these checks after all other tests have been completed,since the ecu is a small pain in the ××× to remove from behind the passenger kick panel.
Good luck EEC-IV