shakes at idle

[jacksheadache]

Is it normal to shake at idle? If I sit and watch the rpm tach it doesn't move but I can feel the truck shake.. it's nothing crazy but want to find out if it's normal or if not how I can fix it.

My mother in law has a newer f150 with the 5.4 in it.. and it does the SAME thing..


any ideas?


thanks!

[Wicked_Sludge]

it depends on how bad the shake is. this sort of thing is almost impossible to diagnose over the internet.

its probably normal. but if its a bad shake, it could be caused by any number of things (such as an engine in need of a tune-up).

[jacksheadache]

Yeah that could be.. I have no idea how many miles the plugs and wires have on them.. maybe i'll do that tonight too.

I wouldn't say it's really bad.. but it's to the point where I can see my radar detector shaking.

It's only when the truck is in park at idle... other then that it runs pretty good.

[jacksheadache]

Well I did the plugs and wires.. the truck is running better but still has a shake at idle.

[Wicked_Sludge]

how many miles are on this truck?

all i can do from here is suggest possible causes so you can dump money into the truck. if you want it diagnosed and fixed (if it even needs fixed), you should take it into a shop.

[jacksheadache]

The truck has pretty close to 74,000 on it now. Should I scan for codes? I don't understand what a shop could check that I can't do on my own.

If it's normal to move a little at idle like this I'm fine with it.. maybe I just need to test drive another ranger to compare and see how they should run.. guess i'm just picky on how the car/trucks run and a small noise I don't understand makes me think something is busted or about to be?

Thing is my mother in laws truck do the exact same thing..

[Wicked_Sludge]

i suggesting taking it to a shop because they have access to a lot more diagnostic tools then the average home mechanic. if there is nothing obviously wrong with the truck, then you need to switch into diagnostic mode, which requires checking things like compression (a cylinder balance test would help), fuel pressure, injector leakdown, ect.

and most mechanics would be able to tell right off the bat if the vibration is above an acceptable level. like i said, this kind of thing is hard to diagnose over the internet since i cant expirience the truck running first hand. there may be nothing wrong with it...and i hate to start suggesting parts for you to replace if we're just chasing a ghost...know what i mean?

[jacksheadache]

Got it.. that might not be a bad idea then..
For now I'm going to leave it be.. because I've started to think it's normal. If things get worse maybe i'll have someone else check it out


thanks again!

[omatous]

My 4.0 liter v6 was idlling around 5-600 and would stall out. I adjusted to up and now its at 1000 and runs smooth. Without pressing gas peddle I am going 15 miles /hr in drive. It seems I should adjust idle down a bit. What is correct idle?

[Monty35]

Usually I think people aim for 800 as a good idle speed

[Wicked_Sludge]

its posted on the emissions sticker on your radiator core support.

[KELLY88]

I know this topic is really old but it is the same problem I'm having. I've replaced the air filter, fuel filter, and spark plugs, tested the IAC, MAF and TPS, and thoroughly cleaned the throttle body plate (it was in bad shape). I've also checked for vacuum leaks multiple times with different methods, no vacuum leaks. With each cleaning or part change the shake gets a little better but never completely goes away. I have no check engine light on but had the computer scanned anyway, no codes (not a big surprise). The shake only happens at idle, whether at a stop light with my foot on the brake or with the transmisson in park. Has anybody else run into this and found a solution? I'm out of ideas.

[gw33gp]

My Ranger recently had a rough idle and it would shake and eventually die if I let it idle long enough. I narrowed it down to the PCV system. I changed the PCV valve but it still idled rough. Then I discovered a crack in one of the PCV hoses. I sealed that and now the idle is very smooth again.

[KELLY88]

My Ranger recently had a rough idle and it would shake and eventually die if I let it idle long enough. I narrowed it down to the PCV system. I changed the PCV valve but it still idled rough. Then I discovered a crack in one of the PCV hoses. I sealed that and now the idle is very smooth again.

Checked the PCV valve and associated hosing, no cracks or leaks there either. A new problem I've noticed recently is that after driving stop and go around town for about 20 minutes or so, I get a faint smell of gasoline after turning the engine off for just a split second then the smell goes away. Checked fittings for leaks and tried to track the source but found nothing. Any ideas if this is related to the shaky idle or entirely irrelevant?

[94 splash]

mine did that too until i changed the motor mount on the drivers side.. its like a little shock and the fluid was squirting out if it and i bough a new shock piece and it was all good from thier

[irishblessing]

i know exactly what your talking about i had the same problem i replaced my spark plugs and wires

and almost fixed the problem, every now and then it will come back but very slightly only in when im in

park. It also would happen when i used to sit at a stoplight in drive no it doesnt in drive at all. If it shakes alot

it is probably misfiring and that should be fixed. i would first replace the plugs and wires but know ill probabaly check my pcv valve

[Twizzler09]

Checked the PCV valve and associated hosing, no cracks or leaks there either. A new problem I've noticed recently is that after driving stop and go around town for about 20 minutes or so, I get a faint smell of gasoline after turning the engine off for just a split second then the smell goes away. Checked fittings for leaks and tried to track the source but found nothing. Any ideas if this is related to the shaky idle or entirely irrelevant?

It could be related. Do you have to prime the fuel system a couple times before starting or have extended crank time before it fires up (3-5 seconds)?

Worn motor mounts or a leaking injector can cause this. My Ranger has the idle shake like this too, and I'm pretty sure its a combination of these two items. If you have to prime the fuel system once or twice before cold starting thats usually a pretty good sign of a fuel system issue, could be the check valve on the fuel pump, or a leaking injector.

My suggestion would be to have a shop test your injectors. Soon as I find someone in town that can test mine, going to have this done also. (As I have this problem too)

[bro2]

Did you do a fuel pressure test? Do you have a egr valve on this motor? If you can do a fuel pressure test and if tests ok cylcle the key with the engine off turn the key back off and watch the fuel press guage to see if it drops. This will let you know if you might have a injector bleeding off at idle . EGR valves are bad for sticking slighly open causing a vaccum leak at idle . also check fuel pressure regulator vac line for fuel , This can cause a rough idle and fuel smell . just some things i would check if it was my truck,

[99RangerBoss]

is it normal for the 3.0 to "shake" a little at idle? i notice my shifter seems to shake a little bit both my 99 and my 03 do it they both got vulcans and both had plugs changed.

[redneck15431]

My 94 has always had a little bit of a shimmy to it. Nothing major though. I don't normally notice it though unless I really focus on it when I'm sitting somewhere idling. My mustang also has a noticable shimmy to it. More noticable than my 94 since I put the cam and polyurathane motor mounts in it. I always thought it to be normal and never had any problems that stem off of it.

[Twizzler09]

A certain amount of shaking is quite normal especially on older motors that have never been completely rebuilt. But it does get to a point where its "too much" and its indicating a problem.

[niterider]

my truck only has 43k on it. but in the last 5 years it only went 3000 miles. i had one bad sparkplug. did the fuel filter, thermostat, cleaned the maf, an service recor in the truck said throttle boy had a mouse nest in it awhile back. no c e l and has good power. my friend says they all do it. but i'm going to do that left shock absorbing motor mount. how much is it? my truck is 5 speed so i don't have the automatic to effect it.

[irishblessing]

my shimmy is my transmisson every now and them at idle it moves around a little and you can fell it

[Twizzler09]

my truck only has 43k on it. but in the last 5 years it only went 3000 miles. i had one bad sparkplug. did the fuel filter, thermostat, cleaned the maf, an service recor in the truck said throttle boy had a mouse nest in it awhile back. no c e l and has good power. my friend says they all do it. but i'm going to do that left shock absorbing motor mount. how much is it? my truck is 5 speed so i don't have the automatic to effect it.

Prices on parts vary depending on which parts store you go to and location, best bet is to hit up your local parts stores (I prefer O'Reily's) and see what their going prices are.

[AKBroncoII]

check and make sure your clutch fan is still good. Mine was bad and causing my truck to shake at idle bad, but I could feel it up to 3000RPM's. It was bad enough that it was shaking my shifter and my passenger seat.