Hi there,

I have an 86 Calais that intermittently hesitates after it has been stopped, or when turning corners. Sometimes when turning a corner, or going to go after being at a stop sign / light, and the vehicle will only slowly lurch forward, even if I floor it. It seems to work best if I let off the gas completely and try again (sometimes it takes 2 tries.) Any suggestions on what could be the cause?

Thanks

A few questions for you to answer, like when was your last tune up? How is the idle? Also, does the engine hesitate when your at driving speed and try to accelerate, or only accelerating from a stop? Finally, "when going around corners" could mean even when your doing 45 mph around a bend. By going around corners I assume you mean from a stop turning? You won't have a problem solving this one if you give some more info

A few questions for you to answer, like when was your last tune up? How is the idle? Also, does the engine hesitate when your at driving speed and try to accelerate, or only accelerating from a stop? Finally, "when going around corners" could mean even when your doing 45 mph around a bend. By going around corners I assume you mean from a stop turning? You won't have a problem solving this one if you give some more info

Thanks for getting back to me. The car had a tune-up about 3-4 months ago. It was even doing this before then, it just does it more often now. The idle is fine, just a little fast. I believe the mechanic did this on purpose-something to do with having the vehicle pass aircare. From what I remember new spark plugs were put in and a new cap. The engine doesn't hesitate when at driving speed and trying to accelerate, only from a stop. No idea why I put turning corners there!

Thanks :)

Well, I experienced a hesitation while I was trying to accelerate yesterday, too. I was just driving along, went to accelerate, and the speed didn't change until after releasing the gas pedal and trying again.

A weak ignition coil can cause hesitation on acceleration. Seeing as you had a recent tune-up, your plugs and wires are ok.
Another contributor to sluggish acceleration is a pluged fuel filter, or a failing/inefficient fuel pump. The ignition coil will not be very expensive for your car, and I'm sure you could bolt a new one into place. The fuel pump is a different story.
You need to learn how to test your coil, and perform a fuel pressure test to diagnose these items.
YOu also might concider have your engine compression checked to see if a leaking valve could be contributing to your problem. During some accelerations, a leaking valve on one cylinder could cause momentary loss of power due to that cylinder not building up adequate pressure.
Ignition Coil
Fuel Pressure
Compression
Look in these areas. What is your knowledge about these things? DO you know where to access information about your engine, and do you have or can you afford to spend 100 dollars on a multi-meter and a feul pressure test kit?

Thanks for getting back to me. I'll have to get my step dad to give me a hand with this one. I definitely have a multitester, and he should know how to test most of this stuff. I'll just have to keep my fingers crossed.

With your multi-meter set to OHMS, identify the primary and secondary terminals, and test the resistance across each, compare them to specifications, which can be obtained at the library in a service manual.

Definately test for fuel pressure and even change the fuel filter no matter what, simply for maintenance.

If all that fails to solve the problem, you perform your compression test. Simply take out your spark plugs, screw the tester into the spark plug hole and crank the engine. The dial will indicate in PSI what pressure the cylinder reaches. Test them all. Each cylinder should be no lower than 100 psi.
Take the highest recorded pressure and compare to the lowest recorded pressure. they should not be any more than 70% different.

*Before compression test- diable the ignition and the fuel feed.

*If you note for example a low pressure on any cylinder, take some oil and put it into the cylinder, test again... if pressure rises, the problem is likely worn rings, if pressure fails to rise, problems could be leaky valves, or a leak at the gasket between two adjacent cylinders.

Just thought I'd update the old thread with my possible fix.

I was rummaging around on the passenger side near the ECU and fund a wire that had been a taped up (I believe it was pnk/wht.) It looked to be running from the engine bat to the ECU. Simply touching the wire to investigate further caused it to break, so I ended up splicing in a new wire to replace it. I don't believe I've had any hesitations since then, and that was over a month back. :grinyes:

I'd sure like to know how that wire because damaged, then simply taped up though. I know the ECU was replaced several times, but that's no excuse to leave a busted up wire simply taped there :banghead: