91 ex. running rich and sounds like mis or something

[Fordpwnzchevy]

Ok. Back in august i think it was i cracked a head on my 91 explorer i believe because my thermostat wasnt working. Well, fixed that problem (pulled heads off put a set of used heads on, every gasket replaced on the top end and new thermostat) ever since this thing hasnt run right. I put some pacesetter headers on this engine after the heads, new o2 sensor, plugs/wires. Now i only have the headers/cat on not the rest of the exhaust. It sounds like its misfiring and is running really rich. I dont have the maf hooked up cause when i hook it up it drops my idle down so far my engine dies. I'm so stumped i've been working on this truck for so long and finally decided to post up here. Thnx for advice in advance.

 

[metstalker]

your maf might need cleaning but not hooking that up might cause your engine to run rich. or replace your maf and check the wires for any splits and such good luck

 

[MrShorty]

Have you double checked the placement of the spark plug wires to make sure they are going to the right spark plugs?

Another thing I might do: hook everything up (including the MAF) as it should be, then run the KOEO test. There will likely be several CM codes, but at this point focus on the KOEO codes. If you get anything other than 111 for the KOEO test, resolve those codes.

I might also check the fuel pressure and compression (to make sure all the gaskets sealed).