1988 Chevy Silverado (CARB) 5.0 engine-305?

Question

Hello.

While at idle, (cold or hot), the engine RPMs drop and raise-sometimes it shuts off...Starts right up though... air sound is aperent but no "leaks"- of any kind.

While accelerating from a stop,- power come in pulses, (i had thought it was the transmission-torq converter)...

Once at freeway speeds it seems fine but it then starts to "hesitate" and it still shut off once- starts right up though...

So i had asked similar ?'s i now dont think it's my transmission, i think it may be a sensor, or somthing else???

Later on today I will "rent" the OBD1 and run a check/test on my truck... if i find the trouble i will try to replace it myself...as for the trans, i'm still gonna have the fluid/filter completely flushed.

Thanks for your time let me know what you may think the trouble is.> By the way, truck was babied by a grand father, never drove hard, has 104,635 miles, complete tune-up done about 4 monthsago, no leaks of any kind, no smoke, no overheat,
Nada.
"/JOe

Answer 1

egr valve or vac leak in the intake gasket.to check intake leaks i use a propane torch.dont light it just open it up and run it along the gaskets at the heads and carb while its running.dont get caught up in the moving parts. if it has a leak the torch gas will make the engine run different as its passed over the leak.its good for checking hoses too.good luck

Answer 2

I don't think you have any head or valve problems. Those carburated 305's used a quadra Jet that in my opinion was a piece of sh!t. The Valvoline carb cleaner works pretty good but if it's real dirty then you need to either dip it yourself or have a carb shop basically rebuild it for you to which they'll dip it.
I would replace the vacuum lines because they can leak ever so slightly you won't hear it with the engine running. The hose is cheap just make sure you do one at a time so you don't mix them up.
Another problem associated with your description is the ICM (Ignition Control Module) to which Chevy's are famous for! Cost about $12-$15 for a generic and about $25-$30 for GM. It's located in the distributor, simple to change. What happens is the ICM has a fine wire inside that breaks apart. When the engine is cold it will run some what OK- when hot, it expands and the engine will either run erratically for a while or/and then eventually not at all!
Check out those problems first, also make sure you don't have any shorts in the ignition harness (another Chevy quirk), and see what happens. I think you have either a dirty carburator (with blown power valve- if it backfired) or vacuum leak. Those 305's get upwards of 150,000 if well maintained.
Been fixing Chevy's 35 years!
PS: If you ever want to install a "brand new" engine yourself, PACE PONTIAC! About $1300! Complete long block with oil pan, valve covers etc. Just bolt on accessories, intake and carb and your in business! I've been using them for years and NO problems! You can put the 350 right in there just use your 305 distributor as the wire harness is different for 350. Works fine!

Answer 3

Chevy small block 8 cylinder engines are all rather a lot interchangeable. there's a 350 it truly is an oddball and it has a opposite cooling equipment. I particularly have a 1991 Silverado that someone replaced out the 304 (i imagine it became a 304) to a 350. I had to improve the exhaust equipment and placed an after market promenade chip contained in the ECM. it truly is a severe performance promenade chip and fee about $250. Swapping a 350 for a 350 could no longer be any difficulty fantastically because Suburbans and Silverados are in reality Chevy trucks. note of the gasoline equipment as you want an identical type. The Silverado likely is a TBI the position the carburetor particularly is gasoline injected, Throttle body Injector. fee particularly relies upon on the position you purchase the motor and who installs it. I used to eliminate and replace 350's for a guy and he gave $250.00 in line with R&R. a reliable 350 can fee likely round a grand and a crate motor you are able to call vehicle-aspects places for expenditures. deal with in reality respected persons and ones which have a guaranty of a minimum of 30 days.

Answer 4

Ok here goes
1 check the intake gasket could be an air leak there that you wont hear at idle
2 check your fuel pressure, it could be a clogged fuel filter or the pump not holding constant pressure
3 check or replace the idle sensor
4 pull the timing cover and check the timing chain and gears there should be no slack in the chain, if there is it needs to be replaced
after those checks you start getting into head gaskets and valve problems and I hope it is not those .Good luck to you !

Answer 5

vacuum leak

Answer 6

check your E.G.R. valve