help identify engine problem

[pontiacfieroguy]

I picked up an 89 4cyl 5spd reg cab shortbed truck with an unknown nonoroginal engine with 8 plugs and is fuel injected and the upper intake is spit in two when viewed from the side and I'm having studdering problems. it ran great for first 20 minutes then started a hard stutter that caused the whole truck to shake and also a lack of power I tried downshifting and it was still bad in 3 and 4 gear but revs smooth and freely in neutral. during the studder the check engine light flashes on and off and when not studdering it comes on and goes off intermittently. my temp gauge doesn't wo. rk but I don't see steam and no water in the oil after 2 hour drive. I don't know how to post pics from my phone but if anybody can give me directions ill post engine pics to help identify the engine

 

[Insanejughead]

Your engine sounds like it is the correct one for that year.

Search for "how to do a code reading" or something to that nature to see how to further diagnose what may be happening.

It sounds to me like it has something to do with the ignition and or ignition control module. Posting the codes will help you (and us) figure out a more specific answer to your question.

 

[pontiacfieroguy]

I read through the test procedures in the tech library but I have no clue where the test plug is and couldn't find any info on its location

 

[adsm08]

Do you know where the blower motor is out in the engine bay? The test plug should be right next to it.

 

[pontiacfieroguy]

http://m1076.photobucket.com/albumview/albums/pontiacfieroguy1/8202715f.jpg.html?o=5 I dont see a place to test unless I'm supposed to unplug the wiring harness and test there

 

[adsm08]

Other side of the blower, right up against the fender.

 

[scotts90ranger]

it should be directly behind the power distribution box on the passenger side, between that and the blower motor. The thing came with a little cap that mounted to the power distribution box that said test port or something) but my '90 was missing it and the '89 I used as a donor was missing it too

 

[pontiacfieroguy]

thank you guys so much, I found it and feel like an idiot now. its showing codes 31 and 63. ill replace the tps as soon as I get a few bucks buy what does code 31 mean? on another note it may be the origonal engine, the title says 6cyl but I decoded vin last night and that says it was a 4cyl from the factory

 

[pontiacfieroguy]

figured out why the tps wasn't working http://m1076.photobucket.com/albumview/albums/pontiacfieroguy1/1fc45880.jpg.html?o=0