86 supra problem

Suprajunkie · 06-06-2008, 04:28 AM

I'm assuming you haven't done anything with the car. Start with the highly probable and work your way down. Going right to the fuel injectors is a bit of a leap.

I'd start with a standard tune up, i.e. spark plugs, plug wires, followed by distributor cap/rotor. Check the air filter and replace if necessary.

With the age of the car you'll want to check the vacuum lines and air intake connections. The lines get old and brittle with age/heat. Check to ensure all the connections on the air intake from the the air filter to the throttle body are tight. Also examine the various vacuum lines and hoses for obvious cracks or breaks and replace if necessary. An air leak can cause one to run badly, especially at idle.

If you have access to a vacuum guage, you can verify a vacuum leak. If you don't have one, buy a can of carberator cleaner and with the car running at idle, spray the cleaner where ever you suspect might be an air leak. If there is a noticable change in the engine idle when spraying, there's your leak.

There are still other potential problems, such as the oxygen sensor, cold start sensor, etc...including a malfunctioning injector, but I'd suggest trying the above first.

Is the check engine light on? I'm not sure where your located but most auto parts stores (i.e. Autozone, OReilly's, etc) will check the engine codes for free if you bring the vehicle by.

How many miles are on the vehicle? Do you have any maintenance history on the car?

Hope this helps.

06-06-2008, 04:28 AM	#2
Suprajunkie Stock Join Date: Jun 2008 Location: Oklahoma Posts: 2	Try the obvious I'm assuming you haven't done anything with the car. Start with the highly probable and work your way down. Going right to the fuel injectors is a bit of a leap. I'd start with a standard tune up, i.e. spark plugs, plug wires, followed by distributor cap/rotor. Check the air filter and replace if necessary. With the age of the car you'll want to check the vacuum lines and air intake connections. The lines get old and brittle with age/heat. Check to ensure all the connections on the air intake from the the air filter to the throttle body are tight. Also examine the various vacuum lines and hoses for obvious cracks or breaks and replace if necessary. An air leak can cause one to run badly, especially at idle. If you have access to a vacuum guage, you can verify a vacuum leak. If you don't have one, buy a can of carberator cleaner and with the car running at idle, spray the cleaner where ever you suspect might be an air leak. If there is a noticable change in the engine idle when spraying, there's your leak. There are still other potential problems, such as the oxygen sensor, cold start sensor, etc...including a malfunctioning injector, but I'd suggest trying the above first. Is the check engine light on? I'm not sure where your located but most auto parts stores (i.e. Autozone, OReilly's, etc) will check the engine codes for free if you bring the vehicle by. How many miles are on the vehicle? Do you have any maintenance history on the car? Hope this helps.