reatta has real bad miss when it warms up.

[Guest billys]

some times it will shout off at 50 60 miles per hour. but will start back up it's a 90? 170000. mi.

it's like you turn the key off and right back on. and some times it stays off and you have to restart. and this is while you are driving. if you push it real hard.it will shout off and on. not like a miss not a back fire. like turning the key off and on. when you pull up to a stop sing it will shudder and shout off if you don't rev to 15. Thanks.

Edited March 12, 2014 by billys (see edit history)

[Barney Eaton]

A miss and shutting down are different. Since it is happening after the car warms..... (1) it is something affected by heat (2) the engine computer has switched out of the warm up mode and that changes the way the injectors work and engine timing.

The first thing to check or replace is the coil module. Many owners report that the oooozzz a greenish slime when bad. Coil modules are available at auto parts stores and very plentiful at salvage yards. Maybe others that have had problems can give you some tips when looking for a used replacement.

[DAVES89]

I agree if it is a miss I would look to the Mass Air Flow Sensor. A shut down I would look to the Coil in particular the Ignition Control Module. Does it start right back up after shutting down or does it have to sit for a bit of time to cool off?

[2seater]

Barney is right, they are two different things, however I had a somewhat similar experience, which turned out to be the Crank Position Sensor. Before it would either quit or not start, it would momentarily shut-off the engine while driving, like a hiccup. The erratic behavior was not what I would have expected from a bad CPS, but is another possibility if the MAF and Ignition Module appear to be okay.

[Guest Mc_Reatta]

The first step would be to go into diagnostics and look for trouble codes. The lack thereof and your symptoms do point to the three items that have already been mentioned (ICM, MAF, and CPS), MAF can be tapped and then disconnected while idling to see if there are any changes in performance. While not conclusive, no change in performance tends to rule it out as the problem. Testing of the ICM and CPS is more involved. Ronnie's site has guidance on testing these items. While the ICM is more expensive, it is easy to swap out to test and a backup if good is not a bad investment. The CPS while inexpensive, is hard to get to and you should probably replace the Harmonic Balancer while your at it given your mileage.

You might consider pulling the ICM and taking to Autozone of another FLAPS that can test it, but if it only fails when hot, it may test OK and still not work under the hood. Now is also a good time to do the Padgett ICM upgrade, but if you get a used Delco ICM from a yard, there's a good chance it will be bad.

[rhhuebner]

I have a 1990 Buick Reatta Coupe with similar engine issues. I starts fine when cold but after driving for 15-20 minutes and turned off, it may not start although the starter motor turns the engine over and the fuel system checks out good. I had the plugs and wires replaced and the coil which oozed some oily substance, Also had the ignition module beneath the coil replaced as advised by the mechanic since the oily substance had leaked into it. After this the engine ran smoothly and did not stall or act unusual. It drove fine going home. Next day, my wife drove into town, and it momentarily stalled on coming to a stop in traffic. After waiting a few minutes, it restarted and was driveable. On her return home it stalled again and was towed back to the repair shop. They then replaced the Mass Air Flow Sensor and as I drove it home while driving at a steady pace the engine and the A/C fan shut off with no engine sputter, just as though I had turned the key off. Now I am told by the repair shop that this kind of trouble has been reportedly been connected to a faulty computer control module which must be replaced by an Authorized Buick Dealer due to proprietary software that must be loaded into it. They speculate that the computer may be responsible for the previous coil failure as well. Does all this sound reasonable to any senior expert out there familiar with the Buick Reatta? I love the car, but may have to sacrifice it if appropriate repairs cannot be made.

Edited February 26, 2014 by rhhuebner (see edit history)

[2seater]

The ECM doesn't contain proprietary software except what is in the EEPROM which gets switched to the new ECM. The ECM does need to be for the Vin C engine and are commonly available used, or at a FLAPS. What you describe sounds very much like what happened to mine. There are basic tests for proper Crank Sensor operation in the case of a "no start" condition but what you describe is just what happened to mine with a bad CPS. Connect a voltmeter to the green connector on the drivers side of the engine compartment. Turn the key on and you should see battery voltage for a few seconds and then drop to zero. Without turning the key to off, crank the engine and observe the voltmeter. If you get a voltage reading, the CPS is likely sending the correct signal. If not, replace the CPS. You have hit most of the other major players already. I don't know of any reason the ECM would cause a failure of the ignition module, but is generally just age and is not uncommon.