Car Shudders

[Guest]

I have an 89 reatta with a shuddering stuttering problem. When I start the car it runs a little rough then when it warms up it smooths out a little but not much. When I start to drive it shudders a little almost like its going to die. If i dont let it warm up it usually does die unless i keep the rpms high. When I try to get on the highway it doesnt really shudder, it just feels like its misfiring a little and has hardly any power. Ive found that while going between 60-70 mph it rus pretty good unless i give it a little gas going up slight hill to maintain speed then it really starts to shudder bad. If I let off the gas then gas it harder the rpms jump pretty high and it runs smoother and has more power. When the car goes back into fourth gear after speeding up it will shudder again. Then sometimes it runs pretty good driving normal but usually I have to manually shift it into third gear to pass somebody. When I come to A stop after around twenty minutes on the highway it will run pretty smooth but I think the rpms are a little high around 800. If I sit at a light for minute or so the rpms jump around between 800 and 600. Ive checked the ignition wires, they seem to be fine. I changed the iac valve and replaced all of the vac hoses. Doing so seemed to help a little but the problem is getting slowly worse. Every once in a while I get a check engine light stating a detection of an electrical problem. While running the diagnostic check I have an error code e041 "cam sensor" and the little lights at the bottom EGR OXY and TCC flash or stay on when having the shuddering problem. Would the cam sensor oxygen sensor or EGR vavle cause all of this or does it sound like a combination off all of these. How would I manually check all of these not just with the computer.

Any and all help is appreciated. Thanks in advance.

[padgett]

All of those at once sounds more like a computer (ECM) problem or bad wiring possibly at the bulkhead connector.

[Shelby]

Check the Fuel Pressure.

[2seater]

A miss under load sounds more like a secondary ignition problem than anything else. A cam sensor problem will usually show up at lower speeds rather than at highway speed, as the injector timing may be incorrect, but this is less critical at elevated engine rpm. If the TCC is locking and unlocking, it will manifest itself as a jerkiness, and a misfire will be more evident when the converter is locked. The EGR should be operating while cruising at highway speed, but if it is stuck partially "on" while idling, it may cause the idle to be rough or even die. The O2 sensor may have an effect on driveability but usually shows up as poor mileage. A misfire will tend to confuse the O2 sensor also. The EGR can be removed and cleaned, plus the three pintle valves can be cycled with 12 volts to see if they are operating freely. The one item that is common to most of these items is the ECM, which has been showing up more and more as these cars age, not really a mileage thing, just age. The cam sensor could be wiring, or the sensor, but the most common is the magnet in the cam sprocket falls out. You can check the magnet (interupter) by removing the sensor at the rear of the timing cover, just below the water pump. Remove the one retaining bolt and rotate the engine until the magnet lines up with the hole in the cover. It is best to remove the accessory belt and the magnet will pull on a steel tool fairly strongly if it is there, or look with a mirror. You didn't mention the mileage, but if very high, a new timing chain will help restore lost power if you go after the cam sensor magnet the long way.