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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: richjr74 on October 20, 2010, 12:34:15 pm

Title: Runs rough at startup
Post by: richjr74 on October 20, 2010, 12:34:15 pm

Guys, my 87 TBI 350 only runs rough in the morning at first crank.  When i start the truck it idles perfectly.  In "park" i can press on the accelerator and it revs fine but in gear if i don't go 3/4 throttle at least, it misses or feels like it misses.  After a few miles of driving it run perfectly.  I'm not a mechanic but it seems if it were timing, distributer, plugs, plug wires, etc... these symptoms would be all the time and not just the first time i start it in the mornings.  Anyone experience this? 

Title: Re: Runs rough at startup
Post by: Layne on October 20, 2010, 02:01:49 pm

It sounds like a sensor. Do you have a ses on?

Title: Re: Runs rough at startup
Post by: richjr74 on October 20, 2010, 02:06:14 pm

SES?  Not sure...there is no check engine light on. 

Title: Re: Runs rough at startup
Post by: VileZambonie on October 20, 2010, 09:13:23 pm

Check the vacuum hose going to the map sensor. Make sure it's not too long or kinked etc. Check the engine coolant temp sensor as well. Jump the A&B terminal of the data link connector and see if it has any DTCs

Title: Re: Runs rough at startup
Post by: richjr74 on October 21, 2010, 07:19:24 am

thanks, i'll give that a shot.