Roamer Posted June 2, 2009 Share Posted June 2, 2009 On my mom's 2001, Outback, Automatic Wagon with 123k miles on it hesitates to move when the engine is cold. When you start the car and put it in drive and try to give it gas it will hesitate to the point of not moving and wanting to shut off. The check engine light does not come on and the symptom to me feels like there is no gas getting to the engine and/or the octane level of the gas is very low to ignite, however once the car has been fully warmed up the hesitation goes away but you still feel a very slight and subtle hesitation during city driving, when on the highway it is all fine (once warmed up of course). I have had similar problems with my soobies in the past but all those problems were related to replacing the MAF sensor, as the check engine light is not giving me any codes I suspect that this sensor is fine. The car is now stuck in front of my house and I want to have an idea of what it is before I take it in to a mechanic (I live in NYC and don't trust most mechanics to work on soobies). Any thoughts are appreciated. Thanks!! Quote Link to comment Share on other sites More sharing options...
johnceggleston Posted June 2, 2009 Share Posted June 2, 2009 (edited) oops Edited June 2, 2009 by johnceggleston Quote Link to comment Share on other sites More sharing options...
Roamer Posted June 2, 2009 Author Share Posted June 2, 2009 trans-x atf additive. search for threads here. I appreciate your input, but I highly doubt my issue is tranny related, the car shifts smoothly and fine the hesitation issue that I am having is engine related, in that the engine is not generating any power, but once it does the auto tranny works fine. Quote Link to comment Share on other sites More sharing options...
CNY_Dave Posted June 2, 2009 Share Posted June 2, 2009 I appreciate your input, but I highly doubt my issue is tranny related, the car shifts smoothly and fine the hesitation issue that I am having is engine related, in that the engine is not generating any power, but once it does the auto tranny works fine. If the engine is not revving up (as you say) then yes, it's not the trans. The 4eat (some of 'em) does have a delayed engagement issue where it revs freely for a bit in D before the car starts to move. Sounds like a classic too-lean condition, or maybe weak spark from bad plug wires or old plugs? It may have a stored code stored even if the CE light isn't on, if you can get it to autozone etc. you can get the codes read (if any). Easy to check is look/listen for vacuum leaks. Dave Quote Link to comment Share on other sites More sharing options...
OB99W Posted June 2, 2009 Share Posted June 2, 2009 [...]the symptom to me feels like there is no gas getting to the engine and/or the octane level of the gas is very low to ignite, however once the car has been fully warmed up the hesitation goes away but you still feel a very slight and subtle hesitation during city driving, when on the highway it is all fine (once warmed up of course).[...] You seem to be describing an A/F mixture that is too lean. A common cause of cold start/running problems is a defective CTS (coolant temperature sensor). Of course, since the engine requires a richer mixture than usual when started cold, something else that doesn't allow for the right ratio could cause similar symptoms. Quote Link to comment Share on other sites More sharing options...
johnceggleston Posted June 2, 2009 Share Posted June 2, 2009 oops Quote Link to comment Share on other sites More sharing options...
Rooster2 Posted June 2, 2009 Share Posted June 2, 2009 trans-x atf additive. search for threads here. I read that it is the engine that is hesitating and nearly stalling. This sounds like an engine drive ability problem, not a trany problem. The Trans-X additive solves the problem of the trany hesitating to engage in the forward gear. Quote Link to comment Share on other sites More sharing options...
Roamer Posted June 2, 2009 Author Share Posted June 2, 2009 You seem to be describing an A/F mixture that is too lean. A common cause of cold start/running problems is a defective CTS (coolant temperature sensor). Of course, since the engine requires a richer mixture than usual when started cold, something else that doesn't allow for the right ratio could cause similar symptoms. Interesting, but if it is a defective sensor wouldn't the check engine light come on? Quote Link to comment Share on other sites More sharing options...
Suzam Posted June 2, 2009 Share Posted June 2, 2009 No a CTS doesn't always throw a code when going bad. I had an idle problem on a 2.2 that never had a code but a new sensor cured the issue. I'd try replacing that first. Quote Link to comment Share on other sites More sharing options...
OB99W Posted June 2, 2009 Share Posted June 2, 2009 Interesting, but if it is a defective sensor wouldn't the check engine light come on? Not necessarily -- the ECU can ''believe'' the engine temperature is what the CTS reports. Quote Link to comment Share on other sites More sharing options...
ron917 Posted June 2, 2009 Share Posted June 2, 2009 Interesting, but if it is a defective sensor wouldn't the check engine light come on? The CEL will illuminate if the ECU gets no signal at all from a sensor. An open circuit or short circuit, for example. For some sensors, the ECU will flag it if the reading is outside of a certain range. But if the failed sensor gives an erroneous signal within normal range, the ECU has no way of knowing that. For instance, the coolant temp sensor may indicate that the engine is fully warm when it's really stone cold. It provided a signal, but it's wrong. Quote Link to comment Share on other sites More sharing options...
greenleg88 Posted June 2, 2009 Share Posted June 2, 2009 hmm wow. ive had this problem too. and i think people just came to the conclusion it was cold out. i get strange idle rpms too even when the car is warm. i coudl be driving for a while put he car in neutral and the RPM will be at like 2000.. I had suspected somethign like a coolant temp sensor. .but never actaully thought of doing anything. Quote Link to comment Share on other sites More sharing options...
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