AT 50% throttle my engine starts to vibrate/stutter

[Ademy08]

Alright lately I've been having some trouble with my car, when i am in any gear other than first and give it over 50% throttle my engine starts to vibrate/stutter. In first gear there is only a little trouble but in every gear it somewhat stutters and vibrates with a noise i can't even explain, it sounds like my Yamaha banshee when i foul one of the two plugs. that's the only thing I can think of to explain it. Someone please help me out here. If there are any other questions you have to maybe better diagnose the problem please do so. Thanks.





Adam

 

[brute]

You can pull the plugs and check them out. Also, look to see if your exhaust is vibrating against something. You can also check to see if it's RPM related or speed related (i.e. neutral at a certain speed or neutral revving to see if it does it while parked). Try to find out some more info and get back to us.

 

[Ademy08]

It's not the exhaust or anything rattling of any kind. It's definetely something with the engine. it runs perfect in neutral and revving it. but as soon as there is boost it starts to stutter and the car shakes because of it and you can hear that something isn't right in the engine.

 

[jking29]

Do a boost leak test. You may also want to do all the maintenance if it has not been done. Also pull the plugs and check them out. They should be NGK bpr6es and be gapped @ .028.

 

[Sinner]

Is the studdering constant when you give it gas or is it intermitent, I had a problem like this a few years back and it turned out to be a bad plug wire but for me the studdering was intermitent.

 

[Ademy08]

the studdering is intermittent, it usually does do it. but there are also times that it doesn't.

 

[Ademy08]

here's something else that might help better diagnose the problem, today when i was driving through town for about 3 miles, i started to smell burning oil and I pulled over, I open the hood to see oil everywhere with a plume of smoke and the oil dipstick halfway out of it's hole. I don't have a clue if this could be related to the problem but it could help.

it's also scheduled to go to a garage on wednesday to see if they can find anything.



adam

 

[jking29]

It sounds like you have a bad pcv valve. If the pcv is bad, when you start building boost the pcv doesn't seal and you will pressurize your crankcase with boost and will blow the dipstick out and cover the motor with oil. I used to have the same problem. I bought a check valve and put it into the line between the manifold and pcv valve. I haven't had a problem with it doing that since. Here is a link to the check valve that I bought.

http://www.usplastic.com/catalog/va...ory_name=45&product_id=15641&variant_id=64175

 

[Ademy08]

I just replaced the pcv valve about 2,100 miles ago. that could be the problem though that was mentioned today by my dad's friend who took a quick look at it.

how do those check valves work anyway?

 

[jking29]

The only pcv valve worth running is a factory Mitsu valve. The aftermarket pcv's such as Fram, Autolite, etc. usually won't hold boost brand new out of the box. The check valve is very easy to install. You run a new line from the nipple on the intake manifold to the check valve. Then run another line from the other side of the check valve to the nipple of the pcv valve. It's as simple as that. The check valve will seal up under boost and not let anything past it. Under normal driving conditions where there is vacuum present, it will open and allow the pcv valve to function normally.