Bogging, stumbling, pwr loss then all is fine...

[scalder]

Whenever I start the car in the morning (actually just about any time) it idles fine for a minute then all of a sudden rpm's drop to around 500 and almost dies. It will stay there for a few minutes around 500 barely running then the idle will recover and all is fine.
At first I thought it was the fuel filter but after changing that the problem is still there..It's almost like the gas in the line goes bad and the engine has to wait for good gas to run right. But it's almost every time I start the car that this happens...any ideas? Fuel pressure or pump??

 

[Torinalth]

normal. just something about the mustang... only thing you can do is alter the screw on the TB to not let it drop so low. not the best fix... but an option. mine does it as well, but i usually dont let it sit long enough to drop from initial high idle.

Torinalth

 

[scalder]

Thanks for chiming in Torinalth but this is FAR from normal. It just started doing this a couple of weeks ago. I literally can't accelerate...give it gas and I could barely get out of the way of a riding lawn mower...
Maybe my car just hates this ethanol crap that's in it...

 

[Torinalth]

you said it goes back to normal... was that a mistake? how about stating your problem again, a little more detail, and in different wording if possible... i think i am just misunderstanding your issue.

Torinalth

 

[scalder]

No that wasn't a mistake...It does go back to normal...it's just the first few minutes after I start the car that it runs bad....REAL bad. Idles bad, no power to speak of AT ALL..You could seriously floor it and not accelerate....then like a light switch, all is fine a minute or two or mile down the road later...

 

[Torinalth]

does it only do this when driving? or does it do it if the car is running and parked? if it does it when parked, can you rev the car to high rpms, or does it still bog when parked (in neutral mind you)?

Noticing you have a manual, can you put the clutch in, raise the rpm, and then engague the clutch keeping the RPMhigher? does it get better once you get into the higher rpms, or does it go back to the lower immediatly?

my money is on the tune. since it was tuned by HPP money says they can fix that too... if its getting really bad then the timing could be off, or a variable being missed. cant say for sure, but i dont see equipment failure being the issue.

Torinalth

 

[trinity_gt]

My first instinct is to suspect O2 sensor issues. The entry into the stumbling might be indicative of the moment the system goes into closed loop. If the front O2 sensor(s) are laggy, it may cause this type of behaviour.

 

[Cory281]

My buddies car was doing this and it ended up being the fuel pump.

 

[Pennywise2]

When was the last time you changed your fuel filter?

 

[scalder]

When was the last time you changed your fuel filter?

Thought the same...I changed it on Tuesday afternoon...no better.

Also, I've noticed some detonation... that's never happened in the past. I have a safe tune and never had this problem before. I really thought it was just bad gas but now I'm thinking they're related problems. Fuel pump??