1987 Dodge Colt Rough Idle Vacuum Leak

1987 DODGE COLT
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WAYKOOL77
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  • 1 POST
1987 1.5 liter.someone told me it wasa vaccumm leak .I can start it up when its cold and it will idle high until the choke opens then it idles really rough.and when put into drive it dies.I took the air cleaner off and sprayed carb cleaner all around the carb while running and it starts to rev high. also when I put my whole hand over the carb it revs high ...... shouldnt it die?not this car it ,I t has a fuel heater inbetwwen the carb and the manifold witch is plastic . I changed the gaskets there and it still does the same thing....please help me
Apr 6, 2007 at 12:42 AM
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RASMATAZ
  • ✓Experienced Mechanic
  • 75,988 POSTS
You sure the choke is fully open-before it dies do you see a lot of black smoke from the rear.

Check the EGR first

If the EGR system is leaking or inoperative, it can cause driveability problems, including detonation (knocking or pinging when accelerating or under load), a rough idle, stalling, hard starting, elevated NOx emissions and even elevated hydrocarbon (HC) emissions in the exhaust.

Try spraying around the intake manifold area-when it smooths out you got your culprit-check all vac lines and I mean all.

Chasing down a vacuum leak can be a bear

Best tool to use is the vacuum gauge-
Apr 6, 2007 at 1:24 AM

Suggested Repair

Confirm the choke opens fully. Check the EGR for leaks or improper operation, then spray around the intake manifold and inspect every vacuum line; a vacuum gauge is the best tool for locating the leak.

Conversation Summary

A 1987 Dodge Colt 1.5L idles high when cold, then idles roughly and dies in drive after the choke opens. Carb cleaner sprayed around the carb and covering the carb both raise the engine speed, and new gaskets at the plastic fuel heater did not help. The expert advises confirming full choke opening, checking the EGR, spraying the intake manifold area, inspecting all vacuum lines, and using a vacuum gauge to find the leak.

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