QuestionQUESTION: I have a 99 Chrysler Sebring LXi Coupe with a 2.5l v6 in the shop. We have been going around and around with this car. It came in originally because the distributor died. We replaced it along with a full tune up. The car ran fine for about a day. Then it kicked a check engine light with an egr code. So we replaced the egr valve assembly. It starts and idles fine. If you slowly apply the throttle it will race up and sounds fine. But if you snap the throttle open at any rpm below 3000 it sputters and tries to die. It does it the worst at idle. If you are idling and snap the throttle to WOT it will not race up and just sit there and sputter. It won't actually die unless you hold it at WOT for a long time. We scoped the map and tps and they seem to be fine. I unplugged the vacuum off the new egr valve and that didn't help. We have been banging our heads into a wall trying to figure out what's going on with this thing. Any advice would be greatly appreciated.
ANSWER: Hi Jeb,
Any new fault codes? If not, how about fuel pressure? When you say "if you slowly apply the trottle it will race up and sounds fine", to how high an rpm can you go without sputtering? What is the response on the highway while driving 'at speed'? Compression OK? Timing belt marks lined up? Checked for an ill-fitting vacuum hose connection or crack and have you traced the vacuum hose diagram? PCV valve? Catalytic converter honeycomb loose/out of alignment?
Everything else you have tried seems appropriate. Please let me know how this works out.
Roland
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QUESTION: There are no fault codes, even if you WOT it and let it sputter itself dead it doesn't kick a light. As to how high, it will reach the rev limiter at around 5500 to 6000. If you slowly raise it up above 3000 you can then WOT it and it races up just fine. As long as you keep it above 3000rpm all throttle response seems normal. You can drive it down the highway as long as you never give it more than partial throttle. You can slowly accelerate to highway speed without a problem. I didn't hear a vacuum leak but I have a EVAP smoke machine I can use to make sure. My "MASTER" fuel pressure tester set doesn't have the special tool for this car's fuel rail to test pressure when it's running. {Something me and the Snap-On man will have a talk about.} Compression and timing marks look good, and the flow of exhaust out of the tail pipe seems normal. I appreciate your time on this head scratcher.
ANSWER: Hi Jeb,
It makes me wonder about either the throttle position sensor or its wiring. Perhaps the flexing of the sensor's harness as the engine reacts to being accelerated is causing a weak wire to 'open' or short. Have you checked along the harness for any signs of melted insulation.
Roland
PS: Another thought: How about the spark wires, were those replaced when you replaced the distributor? And the rotor? And the cap? I was recollecting about the 'demand' placed on the quality of the spark when the engine is accelerated hard. You might observe for arcing between the wires, or wires/engine in a darkened setting.
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QUESTION: The new distributor came with a new cap and rotor. I also replaced the wires, plugs, fuel filter, and air filter. The customer only approved putting the cheapest plugs in it, but it had this problem with the champion platniums that came out of it. So I doubt the new cheap ones would cause the exact same problem. I checked all the wires for the TPS and did a "wiggle" test. What are the chances of that new egr valve being stuck right out of the box. I've had a chevy run similar to this and it was an egr valve that was installed backward by the customer, lol. Looking at the scanner the TPS percentage changes when I apply throttle, but it will never rearch 100 percent. I'm probably about to swap it out anyway and see what that does. It just starts to be a pain swapping out parts and guessing.
AnswerHi Jeb,
I 'feel' your pain about chasing a problem by buying parts. Did you set the spark plug gap to .039-.043? On the egr, I believe you can simply look at the stem hidden in the flange area where you will see it has a circumferential slot which should move back and forth as you rev the engine. You can 'feel' if the valve is closed as you move it via the tip of a screwdriver inserted in the slot. The spring-action should put it back to the closed position when you open the throttle or idle the engine. So visually check the motion of the stem. I suppose it could be a defective valve that leaks when closed, but at least check that the stem moves to the closed position when you flip open the throttle while at a mid-rpm level. Even so, you might want to remove it and see if it is air-tight in the closed position.
Roland
