So What do you make of this?

[Fastback]

So, tonight I went and started my car for the first time in 2 weeks since I put it away. I started it and let it warm up so the gauge indicated that it was within range. I gave it some gas and it has a vibe in the motor.

Well from idle at 800rpm its fine and smooth and then when you slowly apply steady pressure to the gas pedal the car starts to shake a little. It seems to do it most at around 1200rpm and increases all the way to 2 grand. The car will vibe also when you quickly rev it to 3k and on the way back down in the rpm range it will also vibe from 2k to 1k and then finally smooth out at idle. Its never done this before. I just purchased the car 2 months ago. Its been in the garage ever since. Only 6,400 miles on the car. Olny mods are K&N FIPK and MAC 2.5 SS Catback. Maybe Im being paranoid, and the car needs to be driven and fully warmed up and lubricated. I was also thinking that it could be a spark issue. Something to do with the plugs? almost feels like a miss. Anyway anyone have this problem? when the car comes out in the spring I plan on a 2.93 pulley, which plugs should I go with everyone seems to be stuck on NGK TR6 will this maybe fix my ackward vibe off idle? any help would be great or just your imput Thank you

Mike

 

[lloyyd]

Bad gas maybe?:shrug: I'd start with checking the plugs. Mine has TR6's.

 

[Fastback]

I put a fresh tank when I put it away and also added fuel stabilizer. I mean, I guess it could be but damn. I've stored my 70 Mustang like this for the last 5 years and it hasnt done this. Maybe I have to wait till spring and drive it down and put fresh gas in it and see if that is the magical cure.

 

[lloyyd]

It sounds dumb, but a couple years ago I had my ATV in the bed of my truck & stopped to fill them both up. While I was riding my quad kept dying, I figured the plug was bad. Then my truck started acting up too, idling real funny & sputtering. I drained the gas in my quad & filled it back up from another station, problem solved. I haven't gotten gas there since. This is the only reason I suggested it, it's never happened before or since then.
You never know.:coolman:

 

[CobraBob]

These type issues are what I don't miss about my past muscle cars. LOL! Nothing like just driving my Infiniti without worrying about stumbles, shakes, mystery noises, clicks, hesitations, etc. :lol1:
Back to the subject, if it just started I would first focus on a fuel/ignition issue.
* Clogged fuel filter
* Bad fuel
* Bad plug(s)

 

[Fastback]

It could be any one of those things. Dang I've only put 70 miles on the car since I got it 2 months ago. It's been in the garage with the car cover on. Put it up with 3/4 tank of fuel from the station I always go to, also added fuel stabilizer. I also started the car 2 weeks ago and this didn't happen but, when it goes it goes. These damn new cars, my old mustang is so much easier to work on. It is so much simpler. I've been into cars for along time and this is the first fuel injected car that I plan on modifying. Its like starting from scratch, with new information. My other Cobra that I sold had no problems a 98 thats been in the family since new, it was also stock.

maybe I'm overreacting, I'll wait until I can get the car out and get some new gas in it and see what that does.

 

[Tobias]

I had the same problem you do.....I expected my terminator to be smooth as silk compared to my 70 cuda. The cuda shook and idled rough, probably just like your 70 Mustang does. This is regarded as normal. The cobra is so new to you and so smooth you feel everything! The stock plugs are fine untill you raise the boost pressure. You have a good plan, drive the car and it will likely smooth out, every gas station gets some bad fuel now and then.

 

[TGO]

could it be the fuel stabilizer? whatever's in that shit is working it's way through your engine.

 

[PhillyCobra]

I would bet on a clogged or sticking injector in this situation. Would first suggest driving the car fully warmed up and getting on it a bit to put some load on the engine and hopefully flush the offending injector. If this doesn't work, I think it's fine to try a bottle of Chevron Techron cleaner.

 

[TheFleshRocket]

On a side note, you've only driven the car 70 miles in the two months you've owned it? There's NO WAY I could have a hot new toy in the garage and not take it out and drive it. I guess I just don't understand.

Also, why bother with fuel stabilizer unless you're going to let the car sit at least several months? I don't ride my motorcycles much in the winter, but once a month if there's an unseasonably warm day, I'll take them out and ride them several miles each to get the fluids moving. Carbureted cars are a lot more sensitive to getting gummed up--they only have gravity and vacuum to move the fuel in most cases. Fuel injected cars have a lot more pressure which helps prevent clogging.

I only use StaBil in my lawnmower (since it won't get used for about 4-5 months) and my girlfriend's bike (she's a wimp, no riding if the temp is less than 65-70F LOL)--everything else just sits with whatever gas is in it. Although I do try to top off the bikes every time I take them out over the winter to minimize condensation in the tank.

 

[Fastback]

Yep only 70 miles, that was the drive home from where I purchased it and then around the rest of that day, other than that thats it. Both my Mustangs get put away in October or November and I bring them out in May or so. I dont drive my 70 unless there is no clouds, I've olny washed the 70 3 times in 5 years, it only needs a wipe down with the California Car Duster every nown and again.

So I'll wait until I can take the car out again and then work everything out, new gas and some more mods, yeah maybe that will do the trick. Now it just bugs me knowing that my car has something wrong with it and I have to wait until it gets nicer to do anything about it. Oh well, thanks for the responses.

Mike

 

[CobraBob]

I didn't realize you haven't had it out much since buying it. I would not worry about the problem right now. I'd would try to drive it more and see if it works itself out after a tank or two of new fuel. I realize winter has hit Washington so you might have to wait until Spring.

 

[Fastback]

So, went to start it tonight, and pull the car cover off and get in turn ignition, starts, I get out and look at the car. I went back to the drivers seat and I see the check engine soon light on? WTF I turned the car off, disconnected the battery and I am hear now. Seriously, WTF I havent even driven the car but 70 miles, only been in boost 1st and second gear, thats it. no abuse, I still need to get used to the car, so I havent driven it hard. This shake at 1 to 2 thousand in the rpm range showed up yesterday. What am i supposed to do, shit. I havent driven it in a month. Could it be the fuel stabilizer? I did another visual of the engine compartment and Mice have eaten some of my wires. The large loom behind the blower what is that. I sorta traced it to the fuel injector area. If that is the case then some people say the vibe at off idle could be the injector that is colgged. well if the wires are chewed up and not firing to the injectors, this could be the stumble. GOD DAMN MICE, LITTLE ****ERS

 

[Fastback]

Anyone