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[quote=”Jnash” post=89496]I have a 88 Suburban with 350tbi when I am in park and I rev the throttle and then release it, it pops and grumbles out the tail pipe. Any suggestions on what it may be?[/quote]
see if any codes are stored.http://www.obd-codes.com/faq/read-gm-2-digit-obd-codes-free.php
Check your ignition timing with a timing light. Also look for vacuum leaks.
http://www.ericthecarguy.com/faq/solving-automotive-performance-issues
+1 on the above post. You might also check the ignition components like the plugs, wires, cap, and rotor. If you strike out with basic tune up stuff, you might want to check the fuel pressure. I believe it should be between 12-14psi. If it’s low, it can also cause the issues you’re having. There’s a lot of additional info in the article that College man posted as well.
Keep us posted on what you find.
[quote=”Jnash” post=89496]I have a 88 Suburban with 350tbi when I am in park and I rev the throttle and then release it, it pops and grumbles out the tail pipe. Any suggestions on what it may be?[/quote]
I have worked on several of this model year Suburban …. a slightly clogged injector may be your problem. Very common for that model year. try using some injector cleaner see if that helps.
Your problem is a certain amount normal. Some older GM trucks had a manifold air injection system that caused that problem also if the diverter valve went bad. I have seen them blow mufflers apart. Not sure if your truck has the system however. Sometimes a cheap muffler will make the noise more noticeable also.
As long as the truck runs well and doesn’t pop on deceleration while driving I wouldn’t worry about it.
[quote=”wysetech” post=89593]Your problem is a certain amount normal. Some older GM trucks had a manifold air injection system that caused that problem also if the diverter valve went bad. I have seen them blow mufflers apart. Not sure if your truck has the system however. Sometimes a cheap muffler will make the noise more noticeable also.
As long as the truck runs well and doesn’t pop on deceleration while driving I wouldn’t worry about it.[/quote]
Well stated I guess I should have went into more detail and more possible causes. Thanks for the back up.
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