1998 Chrysler Sebring Poor acceleration

LORDMORPHIUS79

MEMBER
1998 CHRYSLER SEBRING
6 CYL
2WD
AUTOMATIC
160,000 MILES

Hello I have a '98 chrysler sebring 2.5 v6. The car has very poor acceleration, poor fuel consumption. I have to press down a lot of the accelerator to move the car. 0-30 the car is slow, then it accelerates very quickly for a moment after about 30 mph. The engine and transmission are newly rebuilt. I have pulled the following codes, P0175, PO171, and P0157. So far I have changed the oil and filter, spark plugs and wires, PVC valve, air filter, and the o2 sensor on the exhaust manifold. I cleaned the throttle body and used a fuel system treatment. The car is still running the same. What should I do next. This engine does not have a Mass air flow sensor.

4 Replies

ERNEST CLARK

MECHANIC
1,730 POSTS

First, you have to check your right bank O2 sensor and the circuit. There's a definite failure that could be either the sensor, connector, wiring or computer.

Then you should do a complete fuel system check. Start with pressure check (Key on/engine off) This will tell you the general condition of the fuel pump. Also while in this state, observe for any leak down. If after 15-min you don't have any leakage, move to the next step. If you do, then you'll have to isolate the cause. (Leaking fuel pressure regulator, in-line check valve, leaking fuel injector)

The next step would be checking pressure with the engine running. If it's too low, then you possibly have a clogged fuel filter or leaking/faulty fuel pressure regulator. You'll have to isolate that cause.

Then you'll want to do a flow test on your injectors. (And see if one/more of them are dead)

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Monday, March 15th, 2010 AT 11:08 PM

LORDMORPHIUS79

MEMBER
3 POSTS

Thank you sir. I know how to do the fuel pressure check. But how do I know which is part of the engine is Bank 1 and Bank 2. I changes the o2 sensor on the exhaust manifold that is next to the radiator. Today I notice another 02 sensor on the exhaust manifold that is next to the firewall. There is of course at least one more o2 sensor after the Catalytic converter. At this point I do not know the firing order to this engine or which cylinders are even or odd.

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Tuesday, March 16th, 2010 AT 12:19 AM

ERNEST CLARK

MECHANIC
1,730 POSTS

Bank number one is the same side as the number one cylinder. This is the spark plug closest to the distributor/coil/wires. (The distributor is actually mounted to the cylinder head of bank one)

Your engine either has four sensors. (Five if you live in California)

Each bank has a sensor before the catalytic converter (or pre-cats), and one after.

The firing order of your engine is 1-2-3-4-5-6

1-3-5 are located at bank one, 2-4-6 are on the other side.

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Wednesday, March 17th, 2010 AT 7:37 PM

LORDMORPHIUS79