shake,hesitating,bucking??

this is odd but i came here to ask the same question that i senn in another post.my car shakes bucks hesitates when i get on it.idling is fine.goin slower its fine but if i floor it it starts to buck 1 time it even turned off,and when u floor it i hear a popping sound,not a back fire but sounds liek almost a exhaust pushing out somewhere i guess.so this is why i think im gonna hollow out the cat?i live in pa so its cold here.in the summer it never did it.and also it doesnt do it all the time only for alil while.i dont drive it alot and it doesnt run everyday.so im thinkin my cat is blocked or gettin blocked up then clearin out after some time?is this possible?can it get blocked the unblocked? or maybe the fuel filter? i dont knwo its has 90 k 305 v8. sounds liek alot of ppl are havin this situation.my heat does work good tho.but i didnt check the antifreeze which iwill today. anybody have anythng else to add why this could be happening?
or has any1 hollowed the cat out yet?

it seems liek alot of ppl are having the same type of troubles? i read these post they all seem similar???whast goin on?

i put a paperclip in slot a and b.the check engine lite flashes once pause then twice pause once pause twice pauce etc.thast all it does.am i doing something wrong??it never flassed more than twice. each tiem it was once pause then twice thast it

I had the same problem. Couldn't find the problem for over a year (and I drove it daily). No computer faults.

Then one day, I was cleaning the carb. The engine usually dies when I spray the cleaner into it. It actually revved up. Discovered that it's running lean. Traced it to the carb to intake gasket which had over 300,000 miles on it. Changed the gasket and THEN re-torqued the mounting bolts after several heat/cool cycles. Problem went away.

So, what's happening is that you're running lean for what could be one (or several) of many reasons.

but wouldnt it do it all the time if ti was runnin lean??this is only now and then.can it be condensation freezing soemwhere tank,fuel filter,fuel line? it jsu started to happen when it got colder out

Maybe a clogged fuel filter ? My 85 would stall out going up hills if I had the gas pedal down a lot, then start up again as I let off the gas. The filter was clogged with rust. Changing trhe filter solved the prob.

Im Goin Got Try That .or I Was Even Thinkin That Its Freezing Up In There For Some Reason.whast Ur Guys Suggestions On Leaving It Parked On The Grass? Cuz Thats Where I Have It Parked At.

I'd concur on running lean. Why it's lean I don't know. Could be a weak fuel pump. Have you checked your fuel pressure yet???

not yet.i had the air filter cover off and the gas was sprayin fine i was using my hand to open up the throttle and it revved fine ,whats another way? also it only does it now and then.not a consistent thing jsu when it wants to.also when it was hessitating when drivin if i put it in neutral it didnt make the sputter or popping noise?

It will react differently under load vs. just revving the engine. The computer will adjust the injector pulse width when it senses load on the engine.... This will cause a drop off in fuel pressure. If your pump or your regulator are weak... Then you will get a fuel starvation situation at WOT.

but wouldnt it do it all the time if ti was runnin lean??this is only now and then.can it be condensation freezing soemwhere tank,fuel filter,fuel line? it jsu started to happen when it got colder out


Excellent point. As the engine heats up, you have parts expanding. When it cools, they contract. On mine, it was a progressive thing because after so many heat/cool cycles, the "air gap" got bigger. Eventually, it didn't matter whether it was hot or cold, the gap was there.

fuel pump sending unit

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well it came down to bad plug wires.they where the originals 15 yrs old!!replaced them the cap and rotora dn now it runs perfect again,even stronger! thanks for every1s help