85 SE

T5

when shifting, not when I push in the clutch, but right after I lay off the gas. during a shift.. around 2,200 - 3,200 rpm.

vrrooommmm. pOp ! .. vrooommmmm Pop!, vroooomm

 

sounds like a backfire

something like a clogged cat or timming?

 

ok, you'r dumpin' gas into the pipe. For some reason your car is either running rich or not firing correctly. Check your ignition components, do a compression check, and check the fuel pressure. Look at your catalytic converter right after you drive it. If it's bright red...bad news.

 

Got the same problem. Trying to track it down.

 

Check the timing. TomP's Major TuneUp *Patent Pending* sounds like it could do wonders for you both. Pull the #1 spark plug and see what it looks like. Should be a nice tan color - if not, trouble in the fuel/ignition.

Go run the snot out of the car, then stop and quickly look under at the cat (easiest to do at night) If it's glowing red... it's done gone south on ya.

 

I know the timing's good, I checked it on Saturday. I haven't check the plugs though, I'll do that. As for the cat. It's possible that it's bad because it's happened before.

 

Yeah, check them out... look in the back of any Haynes manual for a nice list of how to read your plugs.

 

Another thing that I've found is very easy and important to check is problems with the intake. Whether it be the MAF sensor, or just checking for leaks between the MAF sensor and throttle body. I had a backfiring problem last summer, and fixing an open circuit at the MAF relay fixed it. (It was setting a code 34.)

 

Easy check for vacuum leaks -

Start car
Let Car Idle

spray some carb cleaner anywhere you think there might be a vacuum leak.

If idle goes up, you found one!

 

What's in the carb cleaner that makes the idle go up?

 

Nothing really... any combustible fluid will work. Just carb cleaner comes out in a nice straight stream, and will clean while looking for leaks