About 2 weeks ago, I was sitting in a parking lot with the car running, and its just died on me. Thinking WTF, I tried to start it but it wouldnt crank. So I waited a minute or two, tried again, and it turned over, but it sputtered badly then stalled again. (its an M6 btw) I was about to work out, so I figured I'd let it sit, go work out, and try again. So I started it up after working out, and it was fine, I drove to the nearest gas station, put a bottle of octane booster/gas treatment in, and it was fine from there on.

Now fast forward about 2 weeks or so to today, I'm driving down the freeway (ironically on my way to the gym) and in 4th gear I'm accelerating somewhat quickly, and I notice my car is hesitating about once a second or so, like in a rythem, and as I'm driving, it slowly gets worse and worse, to the point where in every gear, I can barely give it any throttle, it just hesitates BAD, and when I push in the clutch to shift, it will backfire sometimes real loud. Anyways, I made it to another gas station, put 2 gallons of 91 octane from shell, and also put in another bottle of octane booster. this helps for about 5 minutes of freeway driving, then it slowly starts hesitating again and even stalls out while I'm on the freeway! I barely made it home today, but here are a few things to note:

1. In the military, so I get gas on base all the time, which I'm about to stop doing.
2. My oil pressure gauge is a little low, at normal running temperature I hang around 37 psi.
3. Often while driving, when I come to a stop and have the clutch in, or if I'm coasting down a hill with the clutch in, I notice that my car will almost stall...the rpm's fall to like 200-300, then it 'revs' itself back up to around 1300, and then goes to normal idle. It will do this over and over sometimes.
4. My engine was recenlty rebuild by CJ at CMS, so I don't think there is any problems there, the only mods I have are the forged internals, long tubes and true duals. I don't see how that would cause this issue, just throwing it out there.
5. After getting home, I popped the hood with the car running, and manually gave it throttle, and the engine shook a lot, and CJ mentined to me before that my motor mounts were crap.

Any help you guys can give me would be awesome, as this is my DD and only car. I'm going to check the tightness of my spark plugs when the engine cools, and make sure my wires are good...I know the headers get hot and might have messed one of them up if they came in contact. Anyways, thanks in advance everyone.

 

sounds like a vacuum leak, also when was the last time you changed your fuel filter?

 

Might be your fuel pump giving out on you. Sounds like what was happening to me when I first put in my 255 LPH. It crapped out within a week or so. Bad pump. Anyways, the car would idle a little inconsistent and when I would tap the throttle, it would bog down and stall. Just happened again to me last night! Just put in the 3rd Walbro 255 LPH within the past 2 months. I would check your fuel pressure before you start looking into the engine.

 

keep at least 1/4 tank in your car to save you fuel pump, cuz the fuel keeps the pump cool.

 

let us know what the culprit is. i am curious..

 

I would try the fuel filter 1st. If you can't blow through it or is very hard to, it's clogged.

 

I have a similar issue that just started too. Mine is an A4 and it will start but then the RPMs will drop and want to die so I have to press on the gas to keep it at it's regular idle... once it hits 990 it starts working normally with the exception of 2 days ago when it tried to die on me within a minute after I started it up. I was pressing on the gas but nothing was happening... it kept sputtering... then it suddenly revved up and took off on me. I'm dropping it off at Strictly Performance tomorrow or Monday. If my car is fixed before yours, I will let you know what they found out.

 

+1 on that

 

fuel pump or filter

 

The fuel filter was replaced less thatn 1000 miles ago, so I should be okay there. I talked to CJ, and he also said it sounds like the fuel pump. I'm gonna call the local auto port here around base and have them test the fuel pressure, and maybe change out the plugs as well. In any case, once I find out the problem, I'll let you guys know for future reference. As always, thanks for the input everyone, much appreciated.

 

check the fuel pressure, or do this, have somebody sit inside and u by the gas tank. put the ignition in run and listen for the fuel pump, see how it sounds, if its really loud its the fuel filter, if it makes a sputtering kind of noise then its the fuel pump.

 

I had a lot of hesitation, like a horrible bad miss, when one of my O2s started to take a ****, but it really didn't effect idle, only while cruising. Local shop had a real time scanner that could read the feedback and see one of the sensors was way off. A different time, I had a "hunting" idle problem that would come and go which I completely got rid of just by finding the happy spot on the idle adjustment screw on the TB.

 

I had the local Midas run a fuel system check, they say there is no evidence of any fuel system issues, pump is good, injectors are clean, etc. They said the I am throwing like 7 codes mostly related to air intake and thats the problem. Now, my service engine light has been on pretty much since I had the exhaust put on, Rob at the former Overkill I thought deleted whatever was needed so those codes wouldnt show up but I don't think the codes would cause the problem. In any case, I'm gonna try to get up to Murietta (sp?) in a bit, CJ and myself are gonna check everything for ourselves, take a look at the O2 sensors and spark plugs. Damn car!

 

Just got back from Midas, good thing is they didnt even charge me anything.

First, they told me that my AIR pump is not working at all, I know less than nothing about that.
Second, the codes I'm throwing:

p1415 - air system bank 1
po418 - secondary air injection system relay A circuit
po412 - secondary air injection system switching valve A circuit
po336 - crankshaft position sensor 1 circuit Range/Permormance
po405 - EGR sensor a Circuit low
po416 - secondary air injection system switching, valve B circuit open
po133 - 02 sensor circuit slow response bank 1 Sensor 1

^^^^A bit excessive huh?? Well I picked it up and drove home fine, but its only like 2 miles so..any thoughts on this crap?

 

even if Rob turned off the codes and it looks like he didn't you still have to unplug the air pump.

 

You can just pull the relay for the air system and/or pull all of that stuff out, but I seriously doubt your problems are related to the air or egr system. Mine definately was fixed by a new O2 and wasn't even bad enough to throw an O2 code. I would start there, but po336 - crankshaft position sensor 1 circuit Range/Permormance doesn't sound good and should be checked too.

 

Mine was a leak in the intake mani where the EGR was, previous owner shorten/modified it and it caused a vacuum leak, then my primary 02's took a ****. Car ran bad and threw the lean bank codes. Once I got the EGR block off kit from a sponsor here and had the 02's changed, then had the codes turned off for secondary 02's and AIR/EGR the car has been great.

Although on a strange note, last weekend the car was running like ****, back firing, low on power ect. I pulled over to check for potential loose plug wires, but nothing. I pulled the top of LID off and removed the filter and there was a huge (9-10 inch) piece of foam cooler stuck to the radiator and under the lid. I pulled it out and the car was just fine, freakin crazy stuff I tell ya!

 

Right on. After we replaced the 02 sensors and the spark plugs, it ran great, then after the car had been running for about 15 minutes, we left it on while recharging the AC, and the car just shut off. No sputtering, just off. That crankshaft position code was the issue, CJ replaced the sensor and now the car runs the way it should again. I was ready to drive that thing of the Coronado bridge yesterday.