the other day my car was running rough at idle and a little rough on the highway. yesterday it got even worse, so i pulled it into the garage and checked the timing and it was jumping between like 8 and 10. so i loosened the bracket bolt on the distributor and adjusted it to 4 degrees (it's supposed to be 0 but i figured 4 would give it a little more kick). my chilton's said to disconnect the tan wire... i couldn't even find a tan wire man. so anyway, after i set it to 4, i tightened that bracket bolt back down and shut the car off. about 10 minutes later i started it again and it jumped to 5 degrees BTDC from 4. i've driven it twice since, last night i went to go get dinner and today i had to go to work. i started it halfway through the day to move it to a different parking spot and it's starting to run rough again, and i'm sure i can expect that when i start it to go home (yes i'm still at work) it'll barely make it home again. what in the hell could be causing the timing to jump like that?

 

You need to set the base timing to tdc so the ecm has a reference point with the est disconnected. The est wire is in the loom above the hvac fan motor housing.Now the timing is to retarted because you wer adjusting it and the ecm was Tring to correct.

 

okay that makes sense. but why would it have made the jump to 10 degrees originally?

 

Checking the timing with the est connected the timing will verry based on engine coolant temp, and engine rpm.

 

Put it back where it was and LEAVE IT ALONE.

As long as the bolt is tight, it NEVER changes.

All you will accomplish by messing with it is, (a) confusing yourself as to whether the reason the car now runs WORSE than it did before is because THE REAL PROBLEM is continuing to get worse; and (b) creating yourself extra work that you'll have to do once you find THE REAL PROBLEM, since then you'll just have to go back and put it back where it was before ANYWAY.

Meanwhile, "timing" CANNOT make an engine run rough. Run hot, yes; lazy, sure; hard to start; yes; ping, absolutely; no power, yes; bad gas mileage, of course; but NOT "run rough".

Put it back where it was and leave it alone. Resist all temptations to dink with it. Then begin troubleshooting. Maybe even catch up a little bit on any "deferred maintenance" (realtor jargon for "let it sit and rot and hope it becomes someone else's problem someday") such as replacing the spark plugs, putting in a new dist cap & rotor, change the fuel filter, etc.

 

Alright so I unplugged the est, reset the timing, and it's still running like ****. Any ideas?

 

As said, something other than the timing.

ALWAYS is.

Start there and let us know what you find.

 

as already stated, we need some base line stuff. pull your spark plugs. inspect them. you can find a chart online to compare. go ahead and replace them. pull the fuel filter. try to blow through it. is it restricted? replace it. pull youe cap check your contacts. are they corroded? replace it. are your wires burnt? are they arcing? replace them. start with a tune up, and then we'll go from there.

 

Right on. I apologize if I am kind of a pain. I'm definitely a noob at this, it's the first car I've had the opportunity to actually work on. I probably won't get to it until Saturday but I will keep you guys updated on what I find.

 

Ignition control module. This past week I had the same problem.

 

Good news! It was just a fuel injector. It was pushing fuel like a clogged water gun, flooding my number 7 cylinder and throwing the computer off somehow it seems as well. But she runs like a champ again!

 

that's cool... I have a slight rough idle also and very infrequent stalls, always at low idle.. 'm going to check my injectors as well as the IAC valve and fuel filter etc... gotta start with the basics and try not to just throw money at a problem until it's diagnosed properly..

 

i see you're running a 350 in yours... the thing to keep in mind is mine is a 305 TBI, so i only have two injectors. It could still very well be your problem but keep it in the back of your mind that you've got eight injectors lol.

 

true true.. I figure to do the test with the digital multimeter.. I have heard if one or more is bad it can cause not only a rough idle but also stalls.. trying to figure out the easy stuff to test first.. these newer cars LOL if you call them that scare the crap out of me.. I'm used to my 75 rag top vette.. sooooo freaking simple to work on..