Replaces intake gaskets now my car high idles then dies after about five seconds

Tiny
BRIAN24
  • MEMBER
  • 1990 FORD MUSTANG
  • 5.0L
  • V8
  • RWD
  • MANUAL
  • 134,000 MILES
I just replaced my intakes gaskets today on my mustang and after I put it back together and started it it runs for about five seconds at about 2000 rpm then stalls out and shuts off. Also, it is a swap out motor from a 1993 cobra. Any thoughts or solutions?
Saturday, January 7th, 2017 AT 7:03 PM

9 Replies

Tiny
MHPAUTOS
  • MECHANIC
  • 31,937 POSTS
Sounds like a big vacuum leak, re check manifold gaskets and all vacuum hoses first.
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Saturday, January 7th, 2017 AT 11:03 PM
Tiny
BRIAN24
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  • 9 POSTS
Ok so I took all back apart and sealed it up pretty good and it ran but it still sounded kinda funky so I checked the dip stick and sure enough it had antifreeze in it. Would it be possible that antifreeze leaked into the oil when I took the manifold off? Or do you think there is an internal leak somewhere?
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Sunday, January 8th, 2017 AT 4:53 PM
Tiny
BRIAN24
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Also when I took it back apart I found out that I didn't torque the bolts down at all on the right side. Now I'm beating myself up about that smh. Anyway would that be the cause of the antifreeze in the oil?
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Sunday, January 8th, 2017 AT 5:21 PM
Tiny
BRIAN24
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Also when I was trying to locate the vacuum leak I discovered that I didn't torque the bolts down at all on the right side of the manifold. I'm still beating myself up about that smh.
Anyway do you think that would be the cause of the antifreeze in the oil? And if so then all I would have to do is flush the engine right?
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Sunday, January 8th, 2017 AT 5:25 PM
Tiny
MHPAUTOS
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If it is a wet manifold that is there are water ports in it, if it was loose you would inject coolent into the cylinder and you would get a misfire and steam out of the exhaust, you would need a lot of coolant bypassing but it is feasible. If you had no issue before just do a oil and filter change and use a quality engine flush to help remove the sludge
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Sunday, January 8th, 2017 AT 8:58 PM
Tiny
BRIAN24
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It is a wet manifold and also what would be a good engine flush? And what would the proper way to flush the engine?
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Sunday, January 8th, 2017 AT 9:35 PM
Tiny
MHPAUTOS
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Any brand name engine oil flush, just add to oil and get engine warm and drain oil and change filter, should be fine.
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Sunday, January 8th, 2017 AT 11:29 PM

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