PTS

iTrader: (3)

On two trips so far that I've taken with my 5.7 350 tpi that were more than an hour and a half long after i get off the highway and drive a little i develop an erratic idle and stumbling when i try to move and if i keep trying to move it gets worse and stalls. after stalling if i let the car sit it starts up and runs fine.

somethings obviously heating up or building up with something that causes this. but my temps fine i have a 180 thermostat and it holds at that temp.
short trips its fine
i dont throw any codes

any help wold be appreciated.

Camaro-454

iTrader: (1)

hello. I am having the same problem with my 305 tpi engine. it will run just fine for hours at a time and all of a sudden it starts coughing, sputtering, it has absoultely No Power at all, no acceleration, Nothing. ant this is all of a sudden, out of the blue, without warning. if I'm on the highway I can't even keep it up at 50 miles per hour, and if I'm in city driving, I'm the slowest thing on the road. people look over and see the white 87 Iroc-Z just barely moving, people are blowing their horns, people re practacally walking faster than I am at this point and it's So embarrassing to be driving a car that can beat a Porche, that right now is slower than a kid on a bicycle.

I have replaced these parts as doing a partial tune up. New spark plugs, new rotor, new air filters, and a new distributor cap. the plug wires were fine so I didn't bother with those right now and I didn't bother the coil because the car starts rightback up with no problems. it does stall out too just like you mentioned.

Now, i my case my car's running a little rich, and I haven;t checked the timing yet, ( I don't have a timing light yet ), but I think in my case I may have a vaccum leak, here and there. I'm thinking possibly clogged fuel injectors, but like I said sometimes it's running fine, so I too am stumped about this.

I didn't have all of my charcoal canister hoses hooked up so I have relied on schematics, and I think I have that right. it's running better but it's not perfect and it's not all the time. I read that if that is hooked up wrong that it can have rough idling, loss of power, rough running, stalling, loss of power, al of the things that my car is doing on a fairly regular basis.

I would check for vaccum leaks, make sure everything is hooked up with your hoses, check for clogged fuel injectors, fuel filter, ( mine is new so that's not it ), new air filter, ( mine is new as well ), your canister hoses are all in the right places, and time the engine with a timing light. also check your fuses, ( something that I need to do as well ).

If I can think of anything else that might help you I'll share that with you, but right now that's where I'm going to start.

hopefully this helps you, and let me know if you figure outr something that I haven't mentioned here.

best wishes on getting yours running right as well.

Camaro-454

southbay08

just for the hell of it, check the ohms on the injectors....hot and cold
let us know what you come up with

PTS

iTrader: (3)

Hey sorry it took a while to get back.

camaro-454 I too did the same tune up as you but also I checked my timing and set it to 3 degrees advance and I'm pretty positive I have no vacuum leaks, but I also know for sure that my injectors are good cause I replaced all of them and haven't had a problem with them. Also I replaced the fuel filter.

However I removed my charcoal canister too and closed up my vacuum line for it and the line that goes to the tank i also took off my emissions stuff that runs off the header and to the cat but left the air pump on the pulley system, and again I have no problem with that the car runs great I ran a 13.7 at the track.

My problem might be slightly different though cause my stumbling only happens after i get off the highway after cruising for more than and hour or two so long highway trips.

PTS

iTrader: (3)

What is the sphere thing that has a vacuum line to it under where the charcoal canister went cause I still have the vacuum line running to that. I don't know what that does or if it works with the charcoal canister maybe if you remove one. you need to remove both?

I searched about charcoal canisters and I don't think its needed for operation of the car except to help mask the fumes of gas and route some of the vapors in the intake

PTS

iTrader: (3)

Any Body got anything?

Arvizu9618

iTrader: (1)

@PTS - That's for your Cruise Control

@ Every one else - Sounds like a "vapor lock" problem I insulated my fuel lines especially where they get the hottest, (near the alternator), I still have the problem but not as often.

PTS

iTrader: (3)

im gonna change my fuel pump cause when i had the problem the other day i looked at the fuel pressure gauge in my engine bay that is hooked up to me nos system and it read 4 psi so im thinking the fuel pump is old and getting over worked or hot cause i also only had 1/4 tank of gas and that its getting weak