idle/cruising troubles

[K5Greek]

well my truck always has had a a rough idle when starting her cold. runs like crap and acts like its gonna die til it warms up. im not sure if this is normal so im posting it up. also when its warm it runs rough and acts like its about to die but picks itself up.

noww when accelerating and cruising it feels like my truck is stumbling. just crusing feels like someone puts a load on the truck then takes it off and it keep repeating.


any ideas?

 

[dyeager535]

Sounds like a coolant temp sender. Personally I'd put a scanner on it and check it out first, autozones supposedly will do this for you. Many will just throw another one on, hope it solves the problem.

 

[Leper]

My first guess would be the temp sender in the intake manifold. If you decide to replace it, get the one that has the pigtail with it. Check your coolant level first. A low coolant level can cause the temp sender to read inacurate.

It could be anything from a vacuum leak to the dizzy starting to go out. A loose bolt on the throttle body or a failed gasket there are sure possibilities. Same with any vacuum source including the main brake booster line, or the booster itself.

 

[K5Greek]

k ill give the temp sender a shot tomorrow. and take it from there. thanks

 

[K5Greek]

update... i changed the sender this morning and still no difference. just to help make me feel better is the sender the same as the one on the side of the block? i asked the guy if its the one for the top of the manifold but well.. you know how that goes.

no change in idle/ cruising or acceleration.

im wondering if it a clogged cat or fuel filter but im clueless. the rpms break up if you powerbreak it and it has a loss of power. also gas mileage seems to bee a bit worse.

im gonna try playing around with it some more tomorrow looking at plugs and stuff, didnt have enough time today.

 

[Thunder]

Check ?clean your EGR valve. May be sticking open at idle.. Or EGR solenoid may be bad.
Disconnect and plug and the vac line from your EGR and see if it runs better.

 

[Grim-Reaper]

Its a "Chuggle". technical term from the factory manual. LOL

Probably a vacuum leak. Those plastic pipe vacuum lines are brittle as hell. Check every last inch on the lines.

I chased my ass on my 88 Burb and finely tracked down similar symptoms to a bad gasket under the TBI. It was sucking air from one side. It actually pulled the gasket in enough to make the leak. About the 30th time with carb cleaner I finally hit it in just the right spot for it to get sucked in and change the idle.

Check the line going to the MAP sensor as well. They get baked on the back side of the TBI and crack where you cant see it.


Another possibility is a bad fuel pressure regulator diaphragm. As old as it is they are prone to the diaphragm cracking and failing to hold vacuum. A fuel injection seal kit is available from Advance autoparts for $30 it includes all the gaskets and seals as well as the diaphragm for the fuel pressure regulator. Clean the filters under the injectors as well.

 

[jamber2541]

just an FYI, I had the same problem and I checked and cleaned everything mentioned above and I could not find anything, I finally said the hell with it and was going to start changing gaskets. The first one I changed was the TBI gasket and it has been two days and its still running good.

 

[K5Greek]

yea i found a vacuum leak right around the tbi so i tightened the bolts a bit. it didnt help to much so i think im gonna go change gaskets but i ran into another problem.. which is probably where my original problem came from. my truck doesnt start now. itll crank for years but nothing.

im thinking that accel coil crapped out. i put a new dizzy/ignition module less than a year ago and the coil is maybe 1/2 year older but im not so sure. im also eying up a new fuel filter since i sunk the truck 2 or 3 weeks ago.

anyone have any tips to check if im getting spark/fuel?

 

[dyeager535]

Check for injector pulse with a noid light. Been covered before.

The temp sender is in the intake, it is not the same as the one on the side of the block.

 

[K5Greek]

k got the truck running today but it still has the same problem.. my coil crapped out on me.

i did notice while ill was back there that a few vacuum lines were dry and brittle so im going to replace them along with plugs and fuel filter. maybe tb gasket too if i can find one for my tb spacer.