89GT missing at low rpm

289 · 09-23-2003, 07:17 AM

Hi
I just got an 89 GT and it will hesitate and buck back and forth at lower rpms below 2grand. THe car also revs up and down at idle speed untill it really gets hot then it settles down. What might this be
Thanks

billheis · 09-23-2003, 09:35 AM

Oh boy, could be a bunch of different things, First thing to do is check codes. Also make sure of no vacuum leaks (You can spray carb cleaner around intake and vacuum hose and if rpm raises you found one) Once youve found out codes (Or even if none) post back and might be able to give a little more definate answer.
Bill

289 · 09-24-2003, 01:05 PM

I just wanted to add that the car runs better when it is all warmed up.

billheis · 09-25-2003, 06:51 PM

I'm going to say check coolant sensor and air temp sensor, could also be MAF. You can get code checker at Auto Zone, DAP, even Sears for cheap. Let us know what codes you have.

09-23-2003, 07:17 AM	#1
289 Registered Member Join Date: Jan 2000 Location: Mount Joy, PA , U.S. Posts: 198	89GT missing at low rpm Hi I just got an 89 GT and it will hesitate and buck back and forth at lower rpms below 2grand. THe car also revs up and down at idle speed untill it really gets hot then it settles down. What might this be Thanks

09-23-2003, 09:35 AM	#2
billheis Registered Member Join Date: May 2001 Location: Fernandina Beach, FL 32034 Posts: 178	Oh boy, could be a bunch of different things, First thing to do is check codes. Also make sure of no vacuum leaks (You can spray carb cleaner around intake and vacuum hose and if rpm raises you found one) Once youve found out codes (Or even if none) post back and might be able to give a little more definate answer. Bill __________________ Bill Heiser 90 Convertable 5.0 LX, ported E7s w/ THumper valve job, TFS street, FR 65mm TB, B cam w/1.7 cobra rockers, kirban AFPR, Mac CAI, Mac Headers, off road h, 3 chamber flows, Crane ign. box, 3:73s, Art Carr AOD & 2600 converter

09-25-2003, 06:51 PM	#4
billheis Registered Member Join Date: May 2001 Location: Fernandina Beach, FL 32034 Posts: 178	I'm going to say check coolant sensor and air temp sensor, could also be MAF. You can get code checker at Auto Zone, DAP, even Sears for cheap. Let us know what codes you have. __________________ Bill Heiser 90 Convertable 5.0 LX, ported E7s w/ THumper valve job, TFS street, FR 65mm TB, B cam w/1.7 cobra rockers, kirban AFPR, Mac CAI, Mac Headers, off road h, 3 chamber flows, Crane ign. box, 3:73s, Art Carr AOD & 2600 converter

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09-24-2003, 01:05 PM	#3
289 Registered Member Join Date: Jan 2000 Location: Mount Joy, PA , U.S. Posts: 198	I just wanted to add that the car runs better when it is all warmed up.