Cutting out when under a load.

V

vaprobe87

Registered User
Recently I have been having a issue with 1989 Supercoupe. When i try to give the car more gas when it starts bogging down like going up a hill or when trying to accelerate at lower RPMs it starts cutting out and bucking around. The first time I noticed it was just after changing to replacement IAC from Auto Zone. At first it was barley doing it but the past few days it has been getting worse and doing it more and more.

Any ideas what it could be? The car is a 1989 SC with a 5 speed.
 
Could be a vacuum leak or plugs & plug wires. Ive had that problem and ended up replacing the plug wires even though they tested ok for resistance. If you do this, be sure to seat the wires fully onto the spark plug. You will feel a click when they snap into place.. Its hard to reach a couple of them and hurts your hand, but it must be done that way.
 
Thanks for the quick response. I changed the plugs about two weeks ago but didnt have the money for wires yet. It is possible that one of them may not have been conected good and has started to come loose so I will check those tomorow.

What should the spark plugs be gapped at? I didnt have a gap gauge when I changed them and was going to check the gaps when I changed the wires out but i might as well just do it when I'm going through it tomorow morning.

What is the best way to check for vacuum leaks?
 
Solution to your problem

I too own a 89 SC and experienced similar problems on two occasions.
Both times the cam shaft sensor was the fault.
Hope that helps.
 
This morning I had to go out before I had a chance to check the plugs, but I popped the hood and and checked to make sure the connections at the coil pack and DIS were tight. I checked the bolts and they were a little loose so I tightened them on down and now it seems like the problem is even worse. When I try to even pull out now it starts cutting out. I made it a few miles down the road and had to turn around and come back home. Once the car cools down I am going to check the plug wires and plug gap. If that dont help I will put my old IAC back on and try that.

The car ran fine untill I changed the IAC it would just idle too fast. I changed the IAC and it idles fine but this problem showed up. I bought a stock IAC from a member here becasue I heard the aftermarket ones were no good.
 
Well, it was the plugs after all. The number 2 wire on the passenger side was completly off and was laying on the header. On top of that the gap was way off. When I changed them before I didnt have a gap gauge. I knew the old plugs looked like they were gapped too much so I just made sure the new plugs were gapped smaller than the old plugs.

I pulled the plugs and they were all around .060 or a little more so i gapped them down to the stock .054 and it runs better than ever did now. Just out of curiosity I got the old plugs out of the trunk and checked them and they were gapped at just over .070 :eek:
 
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Glad you got it fixed. It's nice when the 1st thing you look at during trouble shooting nets results. Too bad it doesn't always work like that....
 
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