Car runs bad and check engine light after replacing distributor
 

91 mustang Gt
I replaced distributor after pip went out, used marks from old distributor to set in the new one.. seemed to run ok but a bit of misfire. I reset distributor at tdc instead of by old distributor marks.Ended up being one tooth different. car ran a bit better, until I plug back in the spout and drove it around the block. check engine light came on and car was popping, misfiring, etc. trouble codes 33, 91, 92; and cylinders 1 and 5 failed balance test. Then i put distributor back where it was, but now its the same result. same codes and same misfiring popping/poor idle. Could I have damaged computer when putting spout back in? Any good help would be appreciated. Thank you

Very unlikely you damaged the computer.

since you say it started when you put the spout back in I would recommend you get a timing light and time it properly to 10 btdc. You just cant guess at what the timing is . What is likely happening is your way to advanced on your base timing and when you put the spout in that makes it even more advanced.

but why would those codes come up? the distributor is set to where it was the first time, when it was running fine, so I dont think its the timing. Something must have gotten messed up when putting the distributor in the second time. what could have happened?

Setting the timing with a light is always recommended when you replace the distributer. For some reason, I have never replaced one and managed to have it perfect, even with marking it.

if you didn't use a timing light.......do not pass go do not collect 200............get a timing light ...nuff said

+1 for the timing light, expecially with these computer controlled cars.....

Just to throw this out there, my brother's 91 GT had some distributor issues and when we swapped the one from my car into his (Accel Billetech) the car ran fine for a while then starting acting up and wouldnt run right with or without the spout. Come to find out that when we tightened down the clamp the distributor either advanced or retarded the timing so bad the car wouldnt run. The spark energy was so bad my timing lights quit working! Ending up taking a stock distributor I had with a bad pip and swapping that out and installing that dizzy. Car runs great now.

i timed it with a light at 10btdc, and i changed the egr valve and now im getting a code 34 instead of 33, but it still runs like its tired, no difference

why did the engine light come on only after distributor? when i plug in small vacuum line to egr, the ingine runs horrible and then goes into open loop. When i disconnect it, it idles out alot rougher and it will only idle high. if i idle around 700rpm, it really struggles bad and shakes horribly. It will probably stall out at 600rpm.

Is there vacuum on that line you are hooking to the valve? It should only have vacuum at cruising speeds. If its unhooked and sucking unmetered air thats why it idles like crap unplugged and when plugged in you are dumping exhaust gas when its not supposed to (at idle).