Originally Posted by modelageek

1) test fuel pressure. Pump failure is common. ($20 for the gauge.)
2)check for codes?
3) could the TB have jumped? Inspect the TB. Is it old or new? Is it loose?
4) clean grounds on ICM. The ICM could be bad? You can run a temp ground jumper from ICM to body, does it run better? If you pull the ICM off you need to put new grease behind it?

You can buy an OBD- I code reader for about $25

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Originally Posted by cowboybilly9mile

Did you specifically find any problems during the first part of properly doing diagnostics, and replace them before moving on to the next phase, which would be pulling codes? And when you pulled codes, you did note that there are three groups of codes that apply to the EEC-IV engine management system you have, and that it's VERY important to follow not just the correct sequence in resolving codes withing each group, but you MUST follow the correct sequence of code diagnostics and problem resolution for EACH code within a group, one code at a time, fix, clear codes, test, and if another exists, repeat this process until there is a code free condition. If you did not do this, and if you didn't do the first step in diagnostics before digging into code(s), then the rest was pretty pointless. FWIW, while possible for all these parts to be "bad", the probability of all of them being bad at one is about nil, and was proven by replacing them and the problem not being fixed. With that said advice would be to do the diagnostics starting with a THOROUGH visual (and correct any and all problems and marginal items), then continue on through the diagnostic process. do NOT buy any part until diagnostics prove for a fact that replacing it will fix the problem. If you don't have the FSM and assuming codes are found, it may really help to get a copy. This because, the diagnostic flow charts for resolving codes in the shop manual are easy to follow and make diagnostics a very systematic, organized process.