1992 Roadmaster Wagon sputtering issue

BigReed79

Buick Newbie
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Warners, NY
Buick Ownership
'92 Buick Roadmaster Estate Wagon
Thread starter #1
Good evening all, I am pulling my hair out (what's left of it) trying to figure this out. I have a '92 Roady wagon with the 350 TBI. The problem I'm having is a hesitation (kind of spits and sputters) on acceleration. Here's the really weird part, if the gas cap is on, it runs worse (almost chokes itself out) once you take the gas cap off, it will stay running but still have the hesitation on acceleration. Fuel filter has been replaced and I have also just replaced the spark plugs, wires, cap and rotor. Any advice on this would be greatly appreciated. The new plugs and wired definitely helped but didn't solve the issue. Thank you in advance
 
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16
Buick Ownership
Buick
#2
Let your mechanic hook your engine up to his computer/code reader and it should point you in the direction of your problem....lot easier/cheaper than just replacing parts.....
 

HotZ28

Full Member
6,132
26
48
Buick Ownership
1996 Roadmaster Limited Collectors Edition 58k - 1996 PAU
#3
Codes will not detect fuel deliver problems on the TBI! I had the same problem with my stolen 1988 Chevrolet truck with the same TBI engine (L05). I replaced the fuel pressure regulator in the throttle body and the problem was resolved! Look closely at the fuel spray pattern in the TB when you bump the throttle. If it is a dripping fuel delivery, rather than a clean mist spray, replace the regulator.
The are cheap and easy to replace.
 

BigReed79

Buick Newbie
3
0
1
Warners, NY
Buick Ownership
'92 Buick Roadmaster Estate Wagon
Thread starter #4
Well, after some more investigation found the thin plastic vacuum line from the MAP sensor to the throttle body was broken. Put a new line on and it seems to have corrected the issue. Once it warms up I'm gonna replace all the vacuum lines (it's - 9 here right now and I don't have a heated garage lol)
______________________________
 

BigReed79

Buick Newbie
3
0
1
Warners, NY
Buick Ownership
'92 Buick Roadmaster Estate Wagon
Thread starter #5
Well, that didn't fix the issue. Still surging something terrible. The parts I've replaced are: Plugs, wires (2 were burnt through anyway), canister purge valve, O2 sensor, EGR solenoid (as one of the tits was broken off and needed to be replaced), MAP sensor and the intake manifold temp sensor. The parts cannon is starting to run out of ideas. My next step is the fuel pressure regulator as HotZ28 suggested. I've also been told it could be the distributor ....Seriously losing my mind here. Had it hooked up to a computer and was told it was running lean and to change the O2 sensor....no fix
 
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