Fellow Members,
Took my C4S out after sitting for three weeks and ran fine for over 100 miles. Then, out of the blue while on the highway, I felt some hesitation in the engine speed like a back and forth hesitation in the acceleration. It lasted about a quarter mile and ironically the odometer just turned 32,000 miles. Was the ECU recalibrating itself at this mileage in life?? Did bad gas go through the lines to create this feeling?? I have a fabspeed cold air kit with BMC filter in OEM air box but that was several hundred miles ago with no ploblems since. For what it is worth, after that quarter mile the car run pheonominal as though nothing was felt.
Please give me your opinion on this description, thank you

 

Hesitation sounds like running out of gas. Could be some buildup in the fuel filter, though 32k is a bit light for that. Put in a tank of 100 oct and drive it hard, clear out the junk.

 

Tank was half full with 93 octane

 

First of all, 100 octane fuel or 200 octane fuel will do absolutely nothing to clean the fuel system, so forget that. If you are running 10% ethanol fuel, there is also no need for injector cleaners and the like.

It is very possible a little bad gas passed through the system and will not cause the problem again. I would not worry about something that seems to have corrected itself unless it occurs again.

 

I feel you are right. I filled up at an Exxon dealer that I was unfamilar with. Or simply the fact that the vehicle was sitting for three weeks maybe effected the stail fuel.

 

I wasn't suggesting higher octane fuel cleans out the fuel system, but if he did get crappy 93, or his 93 sat forever and turned into 93-less, then following up with a tank of 100 will help get his average in the car to something the car likes ( >= 91).

Also, there is no 200 octane unleaded, so putting leaded or jet fuel in his car is a ridiculous suggestion unless he wants to buy new O2 sensors. 100 octane, unleaded, to help get thing back in balance.

 

Could be a coil pack getting ready to go bad.

 

thats the only rational suggestion so far, but if your still on the gas thing, it could be that because the fuel sat for 3 weeks the condensation in the tank mixed in and diluted the fuel therefore causing it to have a bit of water mixing through the engine. I'd suggest putting some dry gas just to ensure that you dont have that issue whether or not it was the original cause of your glitch

 

Coil Packs? Where are they located? I thought these engines run through a ECU. If the coil pack goes out what will happen? Engine will not start??

 

Stop reading this thread!!!!! If you only had the problem 1 time, move on with your life, otherwise people are going to suggest things that will drive you nuts.

 

Coil packs sit on top of each spark plug. They will cause missfires before they totaly go out. Sometimes they only happen under load, certain RPM range, they get wet, or go bad because of age.