Car is shaking and AC cut out

[Reserve13]

Hey LSS, its been a while.

My check engine light came on and I'm havin some problems. The car shakes a whole lot and the AC has cut out. It'll randomly stop for a minute or two occasionally, but rarely. Both the AC and the shaking go in and out together.

Its worth noting that i had a couple cats welded onto an offroad h-pipe and it started about an hour after that. But I have no idea why. Its most noticeable at idle and under about 1500-2000rpm

Anybody have an idea of whats up?

[86sleeper]

Were teh cats brand new?
did you damage an 02 sensor?
any possible vacuum leaks?

[Reserve13]

Were teh cats brand new?
did you damage an 02 sensor?
any possible vacuum leaks?

No the cats were the same ones i took off when putting on the exhaust before. I didnt do the welding but i dont think the sensors were damaged. Vacuum leak could be the problem.
Any idea why its causing the AC to go out?

[BigJnSA]

after welding in the cats, did you disconnect the battery, or change the settings on your tuner? (if you have a tuner) if not, disconnect the battery for like 15 minutes to clear the computer and then let it re-learn the new exhaust. worth a shot.... and u sure the cats were installed the right direction?

i dunno about the a/c tho.... thats weird about your symptoms.

what are your CEL codes? if u dont know, get em pulled for free @ autozone and post up what they are.

[Reserve13]

after welding in the cats, did you disconnect the battery, or change the settings on your tuner? (if you have a tuner) if not, disconnect the battery for like 15 minutes to clear the computer and then let it re-learn the new exhaust. worth a shot.... and u sure the cats were installed the right direction?

i dunno about the a/c tho.... thats weird about your symptoms.

what are your CEL codes? if u dont know, get em pulled for free @ autozone and post up what they are.

Thanks for the reply Jason

I've got a tuner. Can I get the codes with that. I'll try disconnecting the battery tomorrow, see if that helps. No idea if the cats were installed the wrong direction :/ I thought those styled cats worked both ways?

Definitely odd about the AC and odd that it well have a random minute or two here and there where everything works alright.

[BigJnSA]

pull your codes & write them down. then disconnect the battery. google the codes & u will find the fixes. im curious if clearing the computer will fix it.

[Reserve13]

pull your codes & write them down. then disconnect the battery. google the codes & u will find the fixes. im curious if clearing the computer will fix it.

I'm really tempted to go do it now lol. But my car is parked 2 blocks away and I'm lazy :P

[Reserve13]

Alright so turns out the tuner I have can't get the codes, but I've got some updates.

After consistently driving the car multiple times a day, the problem went away and everything was okay for 2 days. I then stopped driving as much and it returned. I tried disconnecting the battery for a while and reconnecting, which fixed the problem for a day, but then it came back again. I took the car into a shop to have them check it out and they said the computer needs to be replaced by ford because there is a misfire (I'm not sure, I was talking with them over the phone and thats what I got out of it). I'm going to put the stock tune on it and see what happens.

Anybody have any idea how much a PCM will cost? I think they also said an ignition coil needs to be replaced, but I couldnt really understand what they said about that either. They estimated in all it'd be about 1200 to get things fixed up by Ford.

Idk, I really don't have the money to mess with this. I might have to end up selling the car if its going to cost me this much to get fixed. :/

[BigJnSA]

dude, if its just a misfire, replace the bad coil. should be about $75..... or see if you can borrow someones for a few days to see if that fixes it. (you could also find out what cylinder the misfire is on, then clear the codes & swap the coil onto another cylinder. if a misfire code comes back up on the new cylinder, you know for sure its that coil and replace it!)

[aguilarf]

dude, if its just a misfire, replace the bad coil. should be about $75..... or see if you can borrow someones for a few days to see if that fixes it. (you could also find out what cylinder the misfire is on, then clear the codes & swap the coil onto another cylinder. if a misfire code comes back up on the new cylinder, you know for sure its that coil and replace it!)

+1

Just replace the coil on the affected cylinder. To be sure get the codes read, a misfire code looks like P0305, with the last number being the cylinder that is misfiring.

I have 6 good used coil packs in a box somewhere, if you want to save some $ over buying one new. $10 each.

EDIT: Found this info regarding the AC cutting out:

Ford V-8s use the high data rate (HDR) of misfire detection and may allow up to a 40 percent misfire at idle prior to considering it a catalyst-damaging misfire. Note: A single cylinder misfire = 12 percent (this will be discussed later in this article). It appears that the A/C is disabled with a single cylinder misfire. We verified this condition after the repair was completed. When a single ignition coil was disconnected, the A/C was in fact disabled! In most cases of ignition misfire, the fuel injector is also turned off or disabled on the misfiring cylinder.

From the website: http://www.asashop.org/autoinc/feb2003/mech.htm