98 Cav 5sp 134K miles. I have been having hesitation issues for the past few weeks. Replaced fuel filter, upstream o2 sensor (after head gasket blew last winter), throttle position sensor ( to resolve OBD code), and IAT sensor. Cleaned the MAP sensor as well. I keep getting P0171 engine too lean error codes. I have had the head milled back to normal and installed a new gasket and have had no more overheating issues or coolant loss. Replaced plugs and wires but i think that was before the head gasket issue was fixed. Also ran a can of seafoam thru it using the 1/3 method but got no smoke. the exhaust smells like unburned gas. What seems to be at random, the car will hesitate and show no response from the gas pedal. A scanner hooked up shows the TPS is reading correctly but the car will get very close to just dieing on me. When it starts to chug i can turn it off then restart it and its smooth after that. I have checked my fittings on the TB and noticed i had some liquid in the bottom of it. Its not consistant with the oil, could this be dirty seafoam that wasnt burned up? The TB butterfly valve is clean as a whistle. I am not sure where to go from here. any suggestions on why im still hesitating or what the liquid could be at the bottom of the throttle body?
I had that same problem off and on about 6 months or so and hasn't come back, but I still want to change it soon. It would just come and go, then just stopped happening all together. I haven't gotten around to changing the TPS (that is the problem for me). Went to autozone to use their free scantool, and the TPS was acting up, but ever since he cleared the code, it hasn't acted up, and that was in November, 05.
Heya Brad Werner
You said you changed the upstream 02 sensor on youre cavalier, What about the second one by the cat? My guess would be thats causing the troulbe for unburned gas smell.
Yea my TPS problem was very intermitten as well and some people said you can just clean then and slap them back on. I just spent the $15 for a new one.
And I have not changed the downstream O2 sensor. That is about $100 and most everything ive done to date has been $30 parts or cheaper. Honestly I dont mind the gas smell cause its not that bad unless the car is in close quarters or you bend over by the bumper.
I am most worried about the car wanting to die. I never know when it will happen. Sometimes it stutters at highway speeds and sometimes it stutters at red lights or stops.
How about some new spark plugs?
check all your ground wires
spark plugs were replaced but i found a receipt stating i bought them before i had the head gasket fixed. so i am trying that next week.
where would i start with ground wires? the battery terminals are clean and secure along with the chassis ground.
Vacuum leak? anyone know where to start with this issue being intermitten? hot or cold, slow or fast it just is not that consistant to think that it was a vacuum leak.
The 2nd 02 sensor will NEVER give you any trouble except a CEL.
Gilles
2.3 Ho
I removed the IAC valve actually last week. It was completely gummed up. Not sure if the valve seat is warped or not but I will try it anyway. The gasket has no nicks or cuts so I will put a drop of oil on it and slap it back in. Hopefully that will fix my issues, I have to get her emissions done this month.
Unless you are getting a CEL for the downstream O2 sensor don't waste your money on it. It's only there to check the "effenciency" of the cat. No effect on rich/lean operation.
Don
Sweet, saves me $90. I will try putting the clean IAT back in and see what happens.
Mine does this same thing. I don't get it. Too sporatic to diagnose.
Problem solved!!! IAC valve seemed to have been the problem. Put it back in last night and the idle was awesome. Roughly at 890 rpm and the gas smell from the exhaust went away. I cleared the CEL and it hasnt come back yet. Shifts smooth and no hesitations. No more sputtering or bogging. And the liquid from the TB was Seafoam. I just sucked it out and closed her back up. Hope this helps some other people.
