I am working on a friends 82 impala 305. I am a ford guy and not real familiar with the mid 80s cars anyway. so the thing runs great and smooth and starts even better. but when the rpms get to about 2500 and up in gear it seems like it is bogging down, but only in gear not in neutral. to me this sounds like ignition. is there anything that commonly goes out on these years such as the coil or soemthing. she also says she smells alot of gas fumes. could it be a cat clogged up? any info is appreciated. she is very broke and im trying to help her out. thanks in advance

 

change the plugs, wires and coil. oil change, replace or clean the air filter. If that doesn't work, clean the carb(if it has a carb) or dump some injector cleaner into the gas tank(if fuel injected). that should take care of it. How many miles are on the engine. I have a '92 caprice with a 305 with about 200,000 miles on it, and it seems to lack a little power on the highway.

 

I would check the plugs, but I don't think that would be your problem. It may be your fuel pressure. Is it a 4 barrel or a 2 barrel. (it could be that the secondaries aren't opening.)
It wouldn't hurt to have the fuel press checked too. (keep in mind a engine is an engine, I will agree thought chev'e and ford's can have a common problem all to themseleves)
It wouldn't hurt to clean the carb, but I would replace anything untill you think that could be at least a partial cause ot the problem, unless it is getting old and could be replaced anyeay.

 

kcb37 you get very confusing. replace the plugs but dont, chevy and ford motors are the same but there not, and dont replace anything unless you think it needs replacing? lots of help there. now to the post the first thing i would recomend would be a carb cleaningfirst and if that dosnt do it try a rebuit one. as well as the plugs wires cap and rotor. if it was the cat. you would usualy smell roten egg smell from under the car when the exaust gets hot. hope this helps.

 

Hey, thanks. thats pretty much what I had in mind was to replace all the ignition parts (Cap, rotor, wires and plugs first and see what happens). she had a code pulled from it saying the o2 sensor was bad so we replaced it and it seemed to get worse. so im thinking maybe the bad o2 has fouled the plugs real bad and it just cant ignite good. full throttle runs decent and idle runs good its just at 2500-3000 holding it steady that it dogs down. she said some guy rebuilt the carb for her a few months back. he may have screwed somethin up in it also. Fun fun stuff. thanks for the replies again

 

If this "cat" is the original one the catalyst compound inside is probably spent. You won't necessarily have the "rotten egg" smell ( sulfur).
You mentioned that there was an O2 sensor involved, if the "cat was bad then the sensor would indicate too rich fuel in the exhaust and lean out the fuel at the intake.

 

Although this is an old thread, I would like to add this list of Common Problems with Chevy 305 because someone like me may find it useful.