Throttle blip when idling

[mikeinmn]

Anyone experienced this? I thought I got rear ended or something. Twice now, sitting in a parking lot, engine idling in Park... suddenly the throttle will blip as though I had just tapped the gas pedal. It revs to maybe 1500 RPM or so suddenly enough that I thought someone bumped me until a split second later I realized the tach jumped. It immediately returned to normal idle. It almost like the same throttle blip that we get on startup (which is beautiful music btw )

Also had one instance of hard starting as though it was flooded. This was on a warm start, parked in my garage for a couple hours after a 15 miles drive. It gassed up the garage with rich smelling exhaust pretty good once it took off and then ran rough. Shut it down and immediately started it back up and she was back to normal.

Should I start with a fuel filter? Could it be in need of new fuel injectors? Perhaps run a good fuel system additive through it?

She runs perfect outside of this. Will most likely wait a couple months to see if it gets worse, with a trip to the dealer if it does. I've got 55k miles, and its a 2005 4.8is.

[Zulu95]

Before you start throwing parts at it why not check for codes? Autozone etc. will actually do a free scan for you.

[mikeinmn]

Should have mentioned.. no codes. Was JUST at the dealer for unrelated work and nothing was logged.

[SlickGT1]

Originally Posted by mikeinmn

Anyone experienced this? I thought I got rear ended or something. Twice now, sitting in a parking lot, engine idling in Park... suddenly the throttle will blip as though I had just tapped the gas pedal. It revs to maybe 1500 RPM or so suddenly enough that I thought someone bumped me until a split second later I realized the tach jumped. It immediately returned to normal idle. It almost like the same throttle blip that we get on startup (which is beautiful music btw )

Also had one instance of hard starting as though it was flooded. This was on a warm start, parked in my garage for a couple hours after a 15 miles drive. It gassed up the garage with rich smelling exhaust pretty good once it took off and then ran rough. Shut it down and immediately started it back up and she was back to normal.

Should I start with a fuel filter? Could it be in need of new fuel injectors? Perhaps run a good fuel system additive through it?

She runs perfect outside of this. Will most likely wait a couple months to see if it gets worse, with a trip to the dealer if it does. I've got 55k miles, and its a 2005 4.8is.

I'm at 78k miles 2006 4.8is. Mine did this one time when I bought it. 2 months ago. Almost crapped myself. I've run some techron through it, cleaned maf, new air filter, going to do fuel filter soon, have it in garage already. I don't know what it is. Hasn't happened since. Oh and no codes either. Checked with gt1 as well.

[mikeinmn]

Thanks, I'll do all of the above. Maybe that will help. Made me nervous, like it was going to take off like a Toyota.

[SlickGT1]

Originally Posted by mikeinmn

Thanks, I'll do all of the above. Maybe that will help. Made me nervous, like it was going to take off like a Toyota.

Yea same with me. And our exhausts are loud, so when it did that, it revved quick, almost like an F1 car firing up. I instinctively hit the brakes even though I was in park.

[mikeinmn]

I'm using insane amounts of gas in city driving, with some intermittent hard starts. Highway mileage is great however. Something aint right...

[SlickGT1]

I all depend if I was flying around, but in the city, I'm anywhere between 10mpg to 13mpg. Never more than 13, but sometimes a lot less than 10. If I was really on it, like when it snowed, I was at 7mpg.

Highway my mileage is really good as well.

[mikeinmn]

I have to say I wasnt expecting city mileage THAT bad!

[SlickGT1]

I'm in NYC though. So I have maybe 200 feet before the next light. If I make it that far. Then there is traffic. So I am not surprised at all.