welp replaced all the plugs and now the car, when started, revs up to about 3k rpm, goes down to 400, shakes and dies. if i hit the gas, it starts knocking HARD and dies again so im afraid to start it. this is (or was) the first time i ever did the plugs myself and im afraid ive really messed things up big time now. any thoughts?

 

Did you gap the plugs correctly?

 

All the wires on all the way? Are the plugs correct? Did you break something loose? Did you put the wires back in the correct spots?

 

check that the plugs have no cracks.

check that the plug wire are put on in the right order.

and check the gap.

 

went to autozone, they looked up my car and had one kind of plugs in stock and said they were right. looked in the cars manual and it said the v8's plugs dont need to be gapped. this is all new to me so i thought ok, out of the box they go into where the old ones came. all wires are connected. i only disconnected 2 clips for each plug and both are attached. dont think i broke anything loose. these are the TYPE of plugs that i got...didnt think they needed to be gapped...

 

check the white part of the plug for crack and damage. that would cause this problem.

 

hmmmmmm did you change one plug at a time? sounds weird like something didn't get plugged in right.

 

but to have it on all 8 new plugs?!?! is that even possible?

 

no changed them all at once. hindsight...shoulda did one by one but didnt think it would be an issue.

 

the picture i posted above of that type of spark plug...can that even BE gapped?

 

Looks correct:



L is new design for new heads Dec 07 forward, R is old 2 piece plug:

 

Plug problems don't explain the rev to 3k on start up. Sounds like a big vacuum line may have been knocked off.

 

 

Yeah I read that cleaning the TB & MAF, and not reconnecting properly, can lead to vacuum issues causing idle issues. (He's got 2 threads on this)

https://themustangsource.com/f637/th...4/#post6122979

 

Agree with that ^. Double check all hoses, and also all ground wires in the area. Can't hurt. Make sure everything is back on correctly.

 

Yes they can be gapped by this tool , but the plugs come gapped at about .045 and if you're NA it should run OK with that gap ...

http://www.steeda.com/store/steeda-s...d-mustang.html

 

well after a totally sleepless night of tossing and turning trying to figure out what was wrong i woke up to rain so i couldnt even work on the car right away. waited till it dried out and decided to tackle the problem. i begin to unclip and unscrew the coils when RIGHT IN MY FACE is the ONE HOSE i unhooked! i said to myself, that cannot be the problem can it?! i clip everything back in, screw it all back, put the hose back and VOILA my problem is solved! i cant believe after all that it really was a single hose...AND everyone on here was right all along!!! hahahaha. ive said it so many times but thank god for TMS and everyone on it! dunno what id do without ya's!

 

 

The credit goes to Al. He called it first.

Glad it you got it fixed.

 

Well I'm happy to share with Al, but... ahem... 6.21 v 6.45:

https://themustangsource.com/f637/th...4/#post6122979