Car is missing and surging at idle? What else could it be?
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Joined: Sep 2000
Posts: 151
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From: Cincinnati, OH
Car is missing and surging at idle? What else could it be?
The car is a 88 GTA 350 TPI. It has the following modifications. Free mods, AFPR, Accell Coil, Cap, rotor, wires, plugs. Edelbrock headers, Airfoil, !AIR, Flowmaster exhaust, ported plenum, Airfoil,
160 degree thermostat
The car fires right up and will idle just fine for about 2-3 minutes. Then it will become real rough, and sometimes would stall out, but have solved that problem of it stalling. Here is what I have replaced so far.
Fuel pump and filter
Cap&Rotor, plugs
IAC motor
Pickup Coil inside distributor
MAF Burn off relays, both of them
Unheated oxygen sensor
I eliminated some of the problems the car was having, and this only does this while for instance sitting at a stop light in drive at an idle. It will run like total garbage. Yesterday it surged ahead and I almost hit the car in front of me, that is how bad it can get. The fuel pump was bad so I replaced that thinking it would solve all my problems but to no avail. The car runs perfectly above about 1800rpm. Now the car runs very cool, due to 160 degree thermostat and according to a scan tool, it is jumping in and out of open and closed loop, because the O2 sensor is cooling down real fast. Do you guys think a heated O2 would help this problem? Your opinions are appreciated!
160 degree thermostat
The car fires right up and will idle just fine for about 2-3 minutes. Then it will become real rough, and sometimes would stall out, but have solved that problem of it stalling. Here is what I have replaced so far.
Fuel pump and filter
Cap&Rotor, plugs
IAC motor
Pickup Coil inside distributor
MAF Burn off relays, both of them
Unheated oxygen sensor
I eliminated some of the problems the car was having, and this only does this while for instance sitting at a stop light in drive at an idle. It will run like total garbage. Yesterday it surged ahead and I almost hit the car in front of me, that is how bad it can get. The fuel pump was bad so I replaced that thinking it would solve all my problems but to no avail. The car runs perfectly above about 1800rpm. Now the car runs very cool, due to 160 degree thermostat and according to a scan tool, it is jumping in and out of open and closed loop, because the O2 sensor is cooling down real fast. Do you guys think a heated O2 would help this problem? Your opinions are appreciated!
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Joined: Jun 2003
Posts: 1,054
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From: Ft. Branch, In.
Car: 88 formula WS6
Engine: 305 Lo3
Transmission: 700-R4
180* therm. or stock should put you back in Open loop after warm up. I would try 180* first. Cheaper! you might need a new radiator. I put a new one in mine this summer and it does good to stay up to 180 cruising down the road and I have a 192*. Can't help with the surge problem all I could suggest would be check the TPS and make sure it's not loose.
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