1998 3000gt Base Model with SOHC starts then when warm runs rough and stalls

10

Asked by Aug 11, 2014 at 02:25 PM about the 1998 Mitsubishi 3000GT 2 Dr STD Hatchback

Question type: Maintenance & Repair

Hello
Thank you for your help. Car is a base model with 57k original miles. New tune up, o2 sensors and coil. Stock except for a K&N filter. The car starts runs well, then when warm runs rough and stalls. Dealer checked fuel system and electronics and could not find anything. Crazy! Any help or ideas would be greatly appreciated. Many thanks.

8 Answers

108,745

Try turning ac on when it's idling rough. Does it start idling ok or better now? If so might try cleaning your iac and throttle plate. Pay close attention to the throttle plate edges and the area of throttle body where it and the plate meet.

2 out of 2 people think this is helpful.
10

Thanks - a/c running/off made no difference. The iac looks clean and we cleaned the throttle plate and no change. Any other ideas?

108,745

Iac looks clean but does the plunger move in and out as it should?

1 out of 1 people think this is helpful.
10

Hello Thank you for responding. I played with the car again this evening. It is frustrating, the car will not kick out any codes, no check engine light. The light works and illuminates when starting the car. Ran great as normal for 30 minutes until warm, they ran rough and started to sputter. When I applied the gas it was like nothing was there gas pedal just went down without any engine response, then the car stalled. I was able a couple of times to apply the gas and rev the engine and then it appeared normal at higher RPMs and when I released the gas it came back to normal idle, then a few moments later the car again sputtered and stalled. Every time the car stalled it started again immediately and ran normal for a while before it repeated the above again. Again this only happens after being completely warmed up. It does seem like if I try hard enough I can prevent the car from stalling by revving the engine. Any thoughts would be super appreciated. Thank you.

10

Hi Dandyoun Iac looks clean but does the plunger move in and out as it should? Thanks for responding Can the IAC malfunction as your note above and not throw out a code? Thank you for your time. Regards,

6,015

B7p1 you cannot go by visual inspection on the IACV you need to put a voltmeter to it to check it,, and I agree with Dandyoun its most likely the IACV,,, could also be a bad water temp sensor but my moneys on the IACV,, here have a read on this link and do what it says and youll find out for sure http://www.stealth316.com/2-isc-iac.htm

2 out of 2 people think this is helpful.
10

Hi Daniel Thank you for your response. Can you please take a look at the attached file and let me know your thoughts. I had taken the car to the dealer and they said they tested everything including the IAC and found no issues, however who knows for sure. Wont kick out any codes. Thanks for your time

1 out of 1 people think this is helpful.
108,745

Yes one of these iac can malfunction without throwing any codes. Just a thought but have you cleaned and tightened you negative battery connections on the frame and motor? These cars do all kinds of weird things when this connection is not perfect. Could also be coil or throttle position sensor heating up and failing. Also check plug wires for areas of carbon tracking.

2 out of 2 people think this is helpful.

Your Answer

Add photo

Related Questions

3000GT

Looking for a Used 3000GT in your area?

CarGurus has 89 nationwide 3000GT listings starting at $4,995.

ZIP:

Search Mitsubishi 3000GT Questions

Mitsubishi 3000GT Experts

#1 dandyoun
dandyoun
Reputation 2,480
#2 Daniel Foster
Daniel Foster
Reputation 950
#3 T_S_T
T_S_T
Reputation 260
View All

Related Models For Sale

Used Mitsubishi Eclipse
22 Great Deals out of 1,316 listings starting at $1,500
Used Mitsubishi Lancer Evolution
15 Great Deals out of 504 listings starting at $9,950
Used Ford Mustang
371 Great Deals out of 46,937 listings starting at $1,999
Used Toyota Supra
41 listings starting at $47,888
Used Chevrolet Camaro
144 Great Deals out of 32,807 listings starting at $1,995
Used Chevrolet Corvette
102 Great Deals out of 20,382 listings starting at $3,495
Used Nissan 240SX
18 listings
Used Mazda RX-7
49 listings
Used Honda Civic
498 Great Deals out of 88,833 listings starting at $1,499