i have a 1989 pick up 4x4 with a 2.6 and 5 speed. i am having problems with cold start idle as well as hot engine idle. it idles very rough and low at cold start. after it is warm it idles better but it is up and down like it is searching for proper idle speed. i have recently replaced the oxygen sensor and have just replaced the cold start sensor. i have checked the idle air solenoid on the fender according to alldata information and it shows as bad. i have talked to local isuzu dealer and they say replacing this solenoid will not fix the problem i am having. any ideas?