Car runs like crap when it's hot

rude_life

Member
Mar 30, 2005
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Car runs like crap when its hot outside and it generally ruuns wierd all the time. It kinda lags starting out in the RPM's until it get's going and then it does pretty well, but its always a bit sluggish. I have replaced all within the last month..The fuel filter, fuel pump, fuel pressure regulator, Coolant temp sensor, spark plugs, spark plug wires, 02 sensors, cleaned MAF sensor, Cleaned ACT sensor, cleaned and oiled K&N air filter, adjusted timing to 10 degrees-(anything above that and it pings), and i even ran a can of sea foam through it yet to no avail. What else could i do?
 
Check the coolant temp sensor. If those fail, the ECU cannot manage the engine because it doesn't know how warm the motor is. All the timings, and tables get balled up and it doesnt run right.
 
That sounds like a nice list of things that seemed intuitive to me too. other than recleaning the MAF and ACT soon (since the filter element was recently cleaned and re-oiled), i dont know what to suggest (and this problem was occuring before that, so I am not suggesting this could be an issue).

good luck with it and keep the thread updated. :nice:
 
Maybe the throttle positioning sensor, or idle air control sensor? I dont know much about either one but chit, im willing to try anything. Maybe my injectors are clogged up?
 
I forgot the main part of your thread - when it is hot. i might check the EGR (it only functions when hot). if this issue happens when taking off at NON-WOT situations, the valve might be opening or opening too much. since your idle is normal (EGR open at idle would degrade the idle or cause stalling), it sounds like it is not a complete malfunction or stuck valve, but it might be opening when it should not be. that is a long shot, but like i said, you covered a lot of the same things i would have too.

good luck bud.