Wierd backfire while idling

[slightly_red_MA70]

So when my car warms up and its idling it will backfire every...lets say 45 seconds to a minute?? It has also done it a couple imes while im driving around.

When i took the plugs out they were gummed up with carbon residue, in fact the plug from #1 cylinder had the carbon connecting the electrodes!!!
Im not sure what is causing this. Theres no engine codes or anything so its not that.

If anyone could help me with this that would be great.

P.S. I dont want t spend any big money fixing this motor as in a month or two im throwing a 7mgte in it :-D

 

[IJ.]

Tight valve lash or a burnt valve.

 

[slightly_red_MA70]

It's getting worse but doesnt do it all the time, my rpms drop more when it does it now. It has also done it a few times while driving.

Also noticed the car was backfiring when i downshift, its never done that before.

 

[supra90turbo]

Check your valve lash, as Ian suggested. Hopefully it's an easy fix and it's not a burnt valve. The more you drive, the more damage you will cause.

 

[slightly_red_MA70]

Check your valve lash, as Ian suggested. Hopefully it's an easy fix and it's not a burnt valve. The more you drive, the more damage you will cause.

How would i check that?

 

[IJ.]

Set of feeler guages between the back side of the cam lobes and followers.

 

[slightly_red_MA70]

TSRM tell me what they should be at?

 

[AJ'S 88NA]

TSRM tell me what they should be at?

http://cygnusx1.net/Supra/Library/TSRM/MK3/
Sure does.

 

[slightly_red_MA70]

figured out the problem.....
i feel really stupid now, it was a cracked spark plug.
Replaced the plugs now the car runs fine