I'm supposed to leave on an 1800 mile cross country move tomorrow, and car just started misbehaving today. Looking for some quick advice, thanks in advance!

The first part of the saga is about 2 months ago. I have a 99.5 A4 quattro with the 2.8 engine. It started idling very rough and throwing codes for misfires so I did a lot of reading and research and tried all the cheap fixes first: cleaned the throttle body and MAF, replaced the problematic coolant temperature sensor, new spark plugs, replaced the vent hose (which was trashed), threw in some fuel injector cleaner with premium gas and within a few miles, no more hesitation, no more rough idle, it was all good for 2 months.

Yesterday, I felt a couple very minor hesitations under acceleration and today just got worse. Pretty bad hesitation under acceleration or load going uphill, particularly from 2k-3k rpm. Idle and cruising was fine unlike previously, but acceleration had to be very slow and deliberate. The CEL also made an appearance. Too late to get codes read at the parts store, and my code reader is on a truck somewhere. So I dumped some sea foam into the tank, topped it off, let the car sit a bit, and now it's running like a champ again.

So my question for more experienced folks is, could my problems really just have been dirty injectors? Or do I have a coil pack just waiting to fail and the rest is just coincidence? Most of the threads I've read suggest that a CP is probably the culprit.

I currently have almost no tools and no place to work on the car, so I guess I'm wondering if I should delay my departure and have a garage look at it, or if I should keep using fuel injector cleaner and probably be in the clear.

A little more info: it's a 5 speed, about 120k miles, timing belt/water pump changed about 1k miles ago after the first incident.

 

What octane fuel do you use? I've heard of misfires happening when we use lower octane fuels in our cars.

 

Do you have another ICM (ignition control module) to test with. Now i got a question is you car Manual or Auto? If its a manual does your car seem to bobble off of 1st gear and then slowly pick power up? does it do the same thing on 2nd gear. can you drive on 5 gear @ about 40 MPH without the car bobbling or feeling like it wants to stall? If you are having this problem you may not have a problem with the fuel injectors or your fuel lines. Your problem is most likely coming from the ICM or coil pack. basically the ICM will control your Coil Pack. That is what is going to give the coil pack power to send a reliable spark to you plugs. I think in your 99 A4 you coil pack is built into one solid unit so either way you going to need to replace the entire coil pack so yeah! Even if coil 6 is not functioning you still going to need to replace the entire coil pack.

 

Hi again.
- I'm using 91 octane now. I was running 87 prior to the first incident, but then upgraded.
- It's a 5 speed and does (or rather, DID) display the conditions described by quattrohead15. At the moment it's running fine again.
- Unfortunately I don't have any spare parts to test with.

Thanks for the replies, sounds like I should go get it checked out.