Part throttle bog
 

I just started working on my son's 1987 TPI Camaro. It has a part throttle bog that I can't seem to get rid of. If you mash the gas, it runs good, but if you're taking off normally, it bogs and wants to die. When it's in overdrive and running at low rpm, it will surge. A friend with a scanner said it needed a MAF sensor, so I bought a used one, put it on, and the problem is slightly better, but still there. The car has new cap, rotor, plugs, and wires that my son put on. Just to make sure, I grounded out each plug with a test light and they all had a similar rpm drop. What's should I check next?

Re: Part throttle bog
 

The problem could be several things. I would check the following...

1. The TPS sensor to see if it has any "dead spots".
2. The fuel pressure at the rails.
3. Clean the IAC sensor of any carbon, etc.

Hope this helps!

Re: Part throttle bog
 

Thanks for the help, I keep getting closer, but no cigar yet. I checked and adjusted the TPS and it helped a bit more. Still a slight bog at part throttle, still wants to surge at low rpm in overdrive. I'm going to check EGR valve operation next, what else should I look for?

Re: Part throttle bog
 

Bingo!
Pull and plug the vacuum line to the valve and see if the bog goes away.

Re: Part throttle bog
 

OK........I plugged the vacuum line to the EGR valve and it ran great for about 5 minutes. Once it got up to operation temperature the problem returned. If you accelerate when the rpms are below 2,500, it falls on it's face. Once above 2,500, it runs fine. I'm suspecting some kind of fuel related problem, but how come it runs great on hard acceleration above 2,500 rpm. Any insight or recommendations you can give me would be appreciated........this is starting to get under my skin!:mad:

Re: Part throttle bog
 

Not to hijack,
I have exactly the same issue, I will be interested to see what you have found.
I have:
replaced the IAC,
removed and capped the EGR,
replaced the TPS and set,
replaced the O2 sensor,
new high perf fuel pump (this is a conversion)
I get a code 44 and a hunting idle when in closed loop. This thing has me baffled.

Re: Part throttle bog
 

i had the same problem with my modded 305. once i tuned it and adjusted the tcc points it stopped acting up.