Rough Idle - Pirate4x4.Com : 4x4 and Off-Road Forum

ARAGORN1 · 08-15-2001, 09:49 AM

Here's the problem, I have a 86 s-10 Blazer, I swapped the 2.8l engine to a 4.3L engine. I also Have a 360 air filter and housing on it too.
When I start the truck cold I get a rough idle that eventually dies down and the engine stops. The engine sounds like it it's tring to regain it's vacuum every time I start the engine, this happens every time after it has been sitting for more then 4 hours. I have no codes, and I have checked the ERG which seems to be working fine, I also Have replaces the IAC, TPS, MAP sensors and the PVC valve. I have also sprayed starter fluid along each of the vac lines in the engine compartment, with out a change being noticed. once the engine is warmed up the truck seems to run fine. sometimes when driving the truck and the engine is warmed up the engine will start to race and accelerate, making the truck hard to stop when the break is applied. Does anybody know what could be the problem, or have any ideas?

Thanks

Home Built · 08-15-2001, 05:29 PM

You have a vacum leak somewhere...That would cause the engine to accelerate like that..
Did you Check the brake booster???
and check all the sources?? No cracked lines..

ARAGORN1 · 08-16-2001, 07:10 AM

Where would the break booster be? Is it on the drives side in front of the master cylinder. if so then yes it's holding a vacuum.
the only lines that I have not checked is the lines goin to the transfer case. kinda hard to get under and spray them with starting fluid when truck is running.

anymore ideas?

08-15-2001, 09:49 AM	#1 (permalink)
ARAGORN1 Registered User Join Date: Aug 2001 Member # 6516 Location: Michigan Posts: 17	Rough Idle Here's the problem, I have a 86 s-10 Blazer, I swapped the 2.8l engine to a 4.3L engine. I also Have a 360 air filter and housing on it too. When I start the truck cold I get a rough idle that eventually dies down and the engine stops. The engine sounds like it it's tring to regain it's vacuum every time I start the engine, this happens every time after it has been sitting for more then 4 hours. I have no codes, and I have checked the ERG which seems to be working fine, I also Have replaces the IAC, TPS, MAP sensors and the PVC valve. I have also sprayed starter fluid along each of the vac lines in the engine compartment, with out a change being noticed. once the engine is warmed up the truck seems to run fine. sometimes when driving the truck and the engine is warmed up the engine will start to race and accelerate, making the truck hard to stop when the break is applied. Does anybody know what could be the problem, or have any ideas? Thanks

08-15-2001, 05:29 PM	#2 (permalink)
Home Built Registered User Join Date: Jul 2001 Member # 5734 Location: Redding Posts: 706	You have a vacum leak somewhere...That would cause the engine to accelerate like that.. Did you Check the brake booster??? and check all the sources?? No cracked lines.. __________________ [B]Chicks dig body Damage...[/B] 74 Chevy Fullsize, 39.5 Irocs, D60/FF14bolt, Locked, Lifted, Stroked, Fuel Injected, Hydro assist. with lot's of body damage...

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08-16-2001, 07:10 AM	#3 (permalink)
ARAGORN1 Registered User Join Date: Aug 2001 Member # 6516 Location: Michigan Posts: 17	Where would the break booster be? Is it on the drives side in front of the master cylinder. if so then yes it's holding a vacuum. the only lines that I have not checked is the lines goin to the transfer case. kinda hard to get under and spray them with starting fluid when truck is running. anymore ideas?