T2ae

What if im having this exact issue but the chains were done 10k miles ago

Frank Simpson

There is a secondary pump that feeds fuel to a container inside the tank that houses the primary pump for cooling and to prevent the pump from running dry under hard cornering. When the tank is under a 1/4 the primary runs dry hence the running out of gas symptoms. Went through multiple pumps and a crap load of web pages before I fugured it out.

00911b7S4

Hello everyone! New here. My family has owned Audi's since the early 80's, (1) Urquattro, (2) 200 Turbo, (1) V8 3.6, (1) A3 2.0Tdi (1) A8L 4.2, and I've owned myself a (B8) A5 3.2 Quattro in Upstate New York and before my relocating couple of years ago to the Caribbean and purchasing a daily driver, B7 S4 6Sp Manual. I bought it used having in mind I was purchasing an Audi and Used but it has been very reliable and a BLAST to drive up until a couple days that started throwing misfires codes in random cylinders, having rough idle and even shaking violently at times. I was recently contacted by Audi of San Juan to perform the Takata Airbag Recall - "final fix" and since I was now having these misfiring issues I took my car to the dealer and have it all checked out. Audi of San Juan, however, only accepted my vehicle for the Recall but would not accept it for any repairs whatsoever claiming is their rule to not receive vehicles that they did not continue servicing themselves after their warranty period and were repaired at other shops. Apparently my vehicle, although purchased and serviced until its 40,000 miles mark at Audi of San Juan, was taken elsewhere afterwards by his previous owner and I cant no longer count on Audi myself. They wouldn't even advise on where to take it. I have a feeling their mechanics just don't want to think or get into complex powertrains. I've always purchased new cars so I am not sure this is the rule with all Audi dealerships in the US.

Anyhow, back to the subject, I have similar symptoms with multiple random cylinder misfires, very rough idle and shaking violently at startup and when in low rpms. I've been scratching my head so much over this matter that I am surprised I am not bleeding. I have worked in my own cars and have helped with friend's cars in the past. I've also worked at a GM Powertrain plant in the past as an Intern when in College. However, this car is driving a bit nuts in the sense that everything is so freaking tight and the area so restricted to reach down. My initial thoughts were spark plugs and possibly the coil packs. The last jobs I have done myself since I purchased it at 92,000 miles, were an oil change and filter, got rid of the K&N previous owner had and put on the OEM one, cleaned up the MAF sensor and even the Throttle Body as well. I've also used a couple of Liquid Molly fuel system cleaners as well and the car has performed super well after doing these jobs plus saving quite a bit of money by doing it myself.

I took the car to a Master Mechanic at JPR Motorwerke in Carolina, Puerto Rico. This guy has a very good reputation in the island and works on very high-end performance vehicles. He races cars as well. His assessment indicates that the cause of the misfires in my S4 is due to a faulty intake manifold or its gasket letting air out, not having a good fuel/air mixture and the ECU going crazy trying to adjust. I will take the car on October 7th and let you guys know if this fixed the problem or needs further examination. My intake manifold is quite worn down due to the very high humidity levels the car has been exposed to over the years. A couple of the corners of the intake manifold case where the screws attach and hold the gas line for the injectors dispensing, have melted away overtime -just the metal part though, I don't see or feel any air coming out although if this is what it looks from above, maybe it does look worse where I cant see below or maybe is just he gasket that is torn.

(B7) Audi S4 V8 6sp Manual - Fully Equipped - White Exterior Color - 95,007 miles at the time of this post.

00911b7S4

johnzadar

check cam lobes

Gearhead 56

John, thanks for your input.

After doing some checking, I found that the vacuum lines to the EGR valves had succumbed to heat, and had cracked. However, this wasn't the cause of the problem. As I was removing the air inlet hose to the MAF sensor so I could replace the RH EGR vacuum line, I saw a 1" x 2" piece of plastic wedged underneath the throttle blade in the inlet of the throttle body. When I checked upstream of the throttle body, I saw that the electronics cover of the MAF sensor was missing. Sure enough, the plastic I found in the inlet of the throttle body was the the missing MAF sensor cover. After replacing the MAF sensor, the engine ran great. I contacted Bosch, and they sent an engineer to my house to verify the issue. He also took the failed MAF sensor with him back to Bosch for further evaluation. I thank Bosch for taking the time out to investigate the issue. My car had ~62K miles.