95 after tune-up, misfiring again

cubanlorenzo · #1 02-22-2005, 11:47 PM

1995 W 4X4 4DR LS. i have already done two FULL tune-ups on my car. i did one right after i bought being that i didnt know who owned it before me so i decided to do one. i also did one after my brother overheated my car and kept driving, schmuck. now again, i have a cylinder 6 misfire. the last tune-up i did was no more than 8000 miles ago. how is this possible? im sure i gapped them correctly. i used stock spark plugs from the dealer. thought that would be the best bet. i guess i was wrong. anything?

Turbocpe · #2 02-22-2005, 11:52 PM

Just wondering, but did the misfire occur immediately after the overheating? And hasn't changed since then?

BlazerLT · #3 02-23-2005, 12:06 AM

How do you know it is #6?

ricksza · #4 02-23-2005, 06:37 AM

Did your tuneup include plug wires, cap and rotor. These can also cause a miss. If the misfire started right after overheating, you might want to do a compression test.

blazee · #5 02-23-2005, 11:49 AM

Have you tried adding a bottle of injector cleaner to your fuel? A misfire doesn't always mean the cylinder isn't getting spark, it could also mean it isn't getting fuel.

Are you losing coolant? Any coolant at the tail pipe? The back cylinders are the most affected by the infamous leaking chevy intake gasket. I hope this isn't your problem, but it is a possibility.

cubanlorenzo · #6 02-23-2005, 11:52 AM

i overheated 8000 miles ago. i have had two misfires since then. one about 3000 miles ago in cylinder 5. i changed that plug out and it was fine. now, 8000 miles after my tune up cylinder 6 is misfiring. i know this because i hooked the scanner up to it. FULL tuneup. everything was done..

BlazerLT · #7 02-23-2005, 12:53 PM

Quote:

Originally Posted by cubanlorenzo

i overheated 8000 miles ago. i have had two misfires since then. one about 3000 miles ago in cylinder 5. i changed that plug out and it was fine. now, 8000 miles after my tune up cylinder 6 is misfiring. i know this because i hooked the scanner up to it. FULL tuneup. everything was done..

I will ask again, how do you know that it is that plug specifically?

cubanlorenzo · #8 02-23-2005, 09:48 PM

i will say again, i know it is the cylinder 6 mis fireing because i hooked the scanner up to it

ricksza · #9 02-24-2005, 06:26 AM

Is this a constant dead miss or an intermittent miss? Pull #6 plug out, is it electrode black or white? That will tell you if you're getting fuel to that cylinder. If it's black, swap #6 plug and wire with another cylinder, that will tell you if you have a bad new wire or plug. Could be possible leaky injector nozzle. If it's white, possible clogged injector nozzle or vacuum leak. If you still can't find the cause, time to do a compression test on all cylinders.

BlazerLT · #10 02-24-2005, 02:30 PM

Check the plug wire connection to #6 and make sure the connection is form and dry.

JoshBarber · #11 02-24-2005, 03:04 PM

hey bud. Not sure if #6 was misfiring before this tune-up or not, but if not, heres

just a suggestion.

I did a tuneup on my girlfriends 98 Mustang GT, and after the tune up, it was misfiring horribly. Hooked it up to a scanner and saw specifically WHICH was misfiring. Turned out that one of the ceramic plugs I purchased was cracked. I know this because I brought them home and installed them right away, and they were never knocked into. I even used a padded spark plug socket. I was told by other people that its happened to them as well.
Pop it out and look real close for a hairline

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