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Hi,
I have a '93 VR4, and everything was working fine until recently.
My engine just seems to cut off. to be more accurate(choking), The engine will fire up each time, would run for about 5-10 minutes. And then the engine would start bucking (Rpm's looks something like ...Start Idle: 1200 would continue for about 2-3 minutes going down to 750 after while; 5-10 minutes then starts to fluxuate lower (engine light comes on) until eventually cuts off) In another scenerio the engine would start up after 10 minutes everything would still seem fine, i would drive the car (keeping Rpm no higher than 3000-3500 before changing gears) maybe for another 10 minutes and the engine would start to buck (Check engine light comes on), and showing on the RPM scale would be something like 3500;quickly jump to 3400 and back up to 3500... due to me holding on the gas. when i would slow down though the idle would eventually drop, only holding the gas will the engine still run.
Note worthy: a grayish smoke comes out when i fire the engine but stops after engine runs for a while.
About 6 months ago i had the spark plugs changed and the fuel pump/fuel filter replaced by mitsubishi which cost me up the rear.
well i wouldnt know if it counts as the same thing...
but before i took it to the dealership, it would periodically "turn off (when the electricals were still on but the power steering went and no gas was able to be applied-rpms dropped to 0 for 2 seconds"- give a good jerk then come back up. (thus the reason i took it to them)and after i took it to the dealership seemingly no problems until recently.

My roommate who owns a mitsubishi told me to check and see if the air was getting into the engine sufficiently; cleaning the intake. Would that help?
Any advice?

Also, if your in the miami area, and willing to help it would be greatly appreciated

not to sure but it could possibly b a misfire situation . but . it hard to really figure out when you not in the car lol .. from what i have learned a bucking and stalling situation could b a misfire . but .. im not sure on .. the smoke part .. but u might want to remeber tis .. white smoke = anitfreeze , blue or grayish = oil , .. now a quick lil test . to find more symptoms would be to ..let the engine run at idle .. and go bye the exhaust and try and smell gasoline .. or unburnt fuel b.c then thats deff .. a misfire.. now you said you changd your fuel pump . did you c any better results. you could check out the injectors .. how many miles is on this thing ?

If it stutters and buck at WOT then its time to invest in some NGK pre gapped plugs and wires... again.

there is about 128K on it. i'll have a look at the smoke today.
thanks for the advice.

so i did inspect the intake and the ISC... and that did not resolve the problem.
i'll give other things a try. and let you know .
Also.. i dont know if this is a "novice" question...but..while i was driving i rev'ed the engine, the guage with the pressure/pounds(the far right one).. would go up half way to maybe 3/5... if i held the gas down for maybe another 3 seconds.. the pressure/pounds would be down to 0 when i looked over again.
again.. not sure if this happens with all cars or not .. im just adding to what i would find suspicious.

and my roommate , who works on his "mitsubishi galant" alot, said that there was "popping" in the front of the engine.

Go wide open throttle (WOT) look at the gauge, If its not pegged to the top by 4000 RPMs something is wrong. It should not peg by just reving.

Also if it sputters at WOT it is your plugs and wires.

sorry but could you elaboarate on what you said.. this is what i understood:
go to the WOT... check or do what to it?(i'm assuming you want me to open it to get some reving-complete novice thinking) ...then looking at the guage if its not all the way up by 4000rpm's then something is wrong.. (the last statement i didnt get.) "it should not peg just by reving"-confused cause you said if its-the guage isnt pegged to the top the sentence before(by increasing the RPM's) that wasnt good and then said it should not "peg" just by reving. ...
i'm sorry it could just be the way i read it being wrong. thanks though for assisting.

Push the clutch in hit the gas that is revving.

car in gear floor it that is WOT (wide open throttle)

The needle on the gauge should be all the way up when you are at WOT

and not when you are clutch in just revving.

sound like your engine ecu is over fuelling, (main processer in ecu is not calculating information correctly ) could be faulty
remove one of your spark plugs after engine stops and see if its excessive black soot these ecu fail regular .

thanks i'll give it a try. and let you know how it goes.

Change the plugs and wires, this will stop your bucking, if it doesn't you have a boost leak which means you need a pressure tester ( you can build on for cheap) and test you intake and intercooler pipes.

To check your ecu pop it open and look for burns or leaky capasiters

yep you were right it was just where you said it'd be


Also, i drove the car today for about an hour before deciding to park it in the Garage. As soon as i got on the incline, the car began to buck again. dont know if this is a sign or not. but i thought i would include it.
I just came from pulling the spark plugs, there was oil at the base and in the threads of one.

So, i became desperate, and went to the dealership to get the diagnostic. They said that it was the Crank A. sensor and the Cam Sensor, thus everything included would cost 500.

i'm debating whether i should let them do it, or i should buy the parts and try it myself. Currently doing research.

I know if they change the sensing blade you mind as well have them do the timing belt as well.

Make them gureentee thats what is wrong with your car. The reason I say that is because thats the first line on the trouble shooting guide.

Do me a favor and take a look at your spark plugs. atleast the front ones.

If they are black or white, change them and the wires first.

So i got the cam sensor and the crank angle sensor done ... and it seems to have fixed the problem.


thanks for everyone who helped!

i made it from miami to austin!