alright i have to explain in a story i dont really know what is wrong. i have an 88 Iroc 350ci TPI with 2.77's i was on my car to Irwindale and it was stop and go traffic and my got got up to 220+ degrees and then my car starts to hesitate the RPM's were jumping down and down like it would go up then down with a jerk and when i try to give it gas it wouldnt go past 3000 RPM it would just Rev like it's relining so then i pull over and waited til it cooled down and it cooled down to about 190 or so degree and started her up and rev it up to 4000 and it was fine drove on the freeway with stop and go traffic and did it again...got to the track and it cooled down and raced all night and it was fine ran strong. then on the way back went on the freeway car was running at 50mph-55mph and temp was 220 go did it again..this time it was backfiring and jerking gave it gas and didnt even Rev. so then waited til it cooled and took the inside streets home it was fine...even got on it a few times it was fine and temp was 220+ until about 6 miles into the drive it did it again hesitating RPM's jerking down gave it gas and didnt Rev. and backfiring. any ideas??? HELP!!!

 

Try getting a scantool hooked up to it to find out what the sensors are doing. Try WinALDL and post the log of a drive where that occurs for us to look at. It may be a CTS issue. Or depending on what exactly is getting really hot, some piece of electronics (like the ESC module) is working only while it's cool. You can usually find these types of problems by heating different things with a hairdryer (don't melt anything!). But like I said, it would really help to get a log to find out where to start looking. Do you have any codes?

 

Man you got me there on the scan tools ect... i dont even have a scaner and there are no codes no SES lights...Don L. thinks its vapor lock(fuel boiling) ?

 

MYH,

First, analyze what the "driving computer" is doing. (That would be YOU.)

You are presuming that the temperature gauge on the dash is indicating the correct temperature. While it provides a relative indication, it is not calibrated to laboratory precision. Also realize that the dash gauge is NOT necessarily reporting the same information that the ECM is getting. There is a separate temperature sensor to feed the ECM, and it may not agree with the dash gauge. Once the ECM gets a temperature over 236°F, it will start to trim fuel pulses, retard timing, hold off the A/C, TCC lockup, etc. In addition, your hotter chambers would promote preignition, causing the ESC to retard timing even more.

From a casual observer's perspective (mine), it sounds like you are not cooling adequately. Make sure the lower air deflector is in position below the lower radiator support, and is intact. Make sure the lower radiator hose is rigid, and does not collapse under the suction of the water pump at road speeds. Make sure there are no air flow obstructions in the radiator (buildup/debris). Check the cooling system for scale buildup (flush). Test the CTS and dash gauge temperature sensor resistances. Test the coolant concentration (anything over 30% reduces cooling efficicency).

It sounds like the ECM thinks the engine is hot, and is compensating.

 

a buddy from my club told me that it could be the pump and it's dieing...my air dam is off the car right now because it fell off about a week ago but its all bent back so maybe it wills till work but ill go to the Chevy dealer and get a new air dam and ill pick up a new fuel pump at work, and flush the rdiator fluid and get a thermo ill see about the senors and stuff thanks for your help guys!:hail: :hail: