Why does my car miss, shake and jitter during acceleration and when its warm?

Tiny
ERIK93GT
  • MEMBER
  • 1993 MITSUBISHI 3000GT
  • 152,500 MILES
I have had this car for one summer so far and three quarters of the way through it started giving me problems. When I take off when its cold it does fine, when it gets warm it doesn't do good. I changed the spark plugs, wires and intake gasket. This helped for one week, and now its back to the way it was. What could it be? Bad coils?
Monday, October 10th, 2011 AT 8:06 PM

7 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Has the check engine light come on? Have you checked for vacuum leaks? Have you checked fuel pump pressure? Crank sensor?
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Monday, October 10th, 2011 AT 9:04 PM
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
https://www.2carpros.com/articles/engine-misfires-or-runs-rough

1.Defective spark plugs
2.Inadequate spark/coil,defective spark plug wire.
3.Lack of compression
4.False air leakage.
5.Faulty fuel injectors.
6.Insufficient fuel pressure.
7.Contaminated fuel.
8.EGR valve that is leaking.
9.Oxygen sensors.
10.Throttle position sensor.
11.Manifold absolute pressure sensor
12.Mass Airflow Sensor
13.Idle air control valve

Note: If it doesn't apply disregard it-
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Monday, October 10th, 2011 AT 9:07 PM
Tiny
ERIK93GT
  • MEMBER
  • 9 POSTS
My engine light has not came on ever. Theres quite a few things it could be. Im going to check the coils for good spark and dead cylinders.
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Monday, October 10th, 2011 AT 9:16 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Let us know what you find.
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Monday, October 10th, 2011 AT 9:21 PM
Tiny
ERIK93GT
  • MEMBER
  • 9 POSTS
Will do. Could it be a possibility that my timing beltslipped or jumped and thats why its running rough? I checked the timing belt that runs the DOHC and its a little loose, can tell its old.
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Wednesday, October 12th, 2011 AT 12:00 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
If it jumped, it would be very rough if it was to run at all. The belt could be stretched. You will need to see if all the timing marks line up at the same time
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Wednesday, October 12th, 2011 AT 12:44 AM
Tiny
ERIK93GT
  • MEMBER
  • 9 POSTS
Hi. I am know working on an air intake for my 3000gt for more air flow. My friend gave me his old air intake off his mitsubishi eclipse 2.0L, it looks like it will fit up right, the only thing I have to do is buy a MAF Sensor Adapter because I need my MAF Sensor for the car to run. Would it hurt if I mounted my MAF Sensor on the new adapter just before the throttle body? Or does it need to be mounted by the air filter?
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Tuesday, November 29th, 2011 AT 3:56 AM

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