87 missing at low RPMs?
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87 missing at low RPMs?
Rebuilt my 87 engine [700R tranny] after an overheat situation cooked the pistons and block--included new wires, new distributor parts, and new ECM. Runs great under hard acceleration or while crusing but under modest acceleration, shifts to 1st and 2nd and 3rd seem normal--including 3rd converter lock-up. But as I accelerate toward 40 MPH and then let off some on the gas, I get what sounds like the engine missing and/or the converter going in/out of lock-up. If I feed it a bit more gas, it all clears--no more missing/shaking. Tried adjusting the TV cable and also had my local vette shop re-program the ECM chip to delay converter lock-up. Only error code I ever get from the ECM is an occasional "34" but it does not seem related to the "engine missing" fits. Any thoughts--could it be injectors?
Safety Car
Joined: Aug 2009
Posts: 3,752
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From: Melbourne, Victoria, Australia
Rebuilt my 87 engine [700R tranny] after an overheat situation cooked the pistons and block--included new wires, new distributor parts, and new ECM. Runs great under hard acceleration or while crusing but under modest acceleration, shifts to 1st and 2nd and 3rd seem normal--including 3rd converter lock-up. But as I accelerate toward 40 MPH and then let off some on the gas, I get what sounds like the engine missing and/or the converter going in/out of lock-up. If I feed it a bit more gas, it all clears--no more missing/shaking. Tried adjusting the TV cable and also had my local vette shop re-program the ECM chip to delay converter lock-up. Only error code I ever get from the ECM is an occasional "34" but it does not seem related to the "engine missing" fits. Any thoughts--could it be injectors?
So if your EGR looks good, jack up the back of your vette and check for any movement in your universal joints.
Safety Car
Joined: Aug 2009
Posts: 3,752
Likes: 276
From: Melbourne, Victoria, Australia
Click the link to an older thread, sounds similar 
http://forums.corvetteforum.com/c4-t...e-this-ww.html
http://forums.corvetteforum.com/c4-t...e-this-ww.html
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WOW--never would have guessed u-joints. Had the drive shaft out during the engine rebuild and didnt notice any issues there--though guess it could have gone bad in the interim 5k miles. Are there some "telltale" signs to look for with the half shaft u-joints? Joints are cheap enough but can't imagine the effort required to change them out--guess its time to get out the old FS manual.....
