305 TBI, won't idle and surges when runs
09-26-2014, 04:06 PM
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305 TBI, won't idle and surges when runs
My 88, 305 TBI/5 spd had been sitting for a while, but started regularly. Not long ago, when I started it, it would idle really high 3500 or so, and then drop to almost nothing and keep doing that. Once I got it warm, it would idle right. I'd hold it at 2,000 to warm it. When I drove it, it would drive ok if real ginger on the accelerator. Any real acceleration and it would stumble and buck. The problem continued to worsen and eventually wouldn't idle but did kick a code. MAT sensor and TPS. I've replaced both. It's still doing the idle issue but won't start idling even once warm now and won't stay running even when trying to hold at 2,000. No codes are showing up. HELP!? 
I read thru a few posts, but haven't seen the same scenario, so any thoughts are appreciated.
I read thru a few posts, but haven't seen the same scenario, so any thoughts are appreciated. 
09-26-2014, 08:08 PM
#2
Re: 305 TBI, won't idle and surges when runs
Check the fuel pressure, you'll need an adaptor to test it. Autozone rents out tbi testers that includes the adaptor. Spec is 9-13 psi. These cars will run on very low pressure.
09-29-2014, 02:38 AM
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Car: 91 RS
Engine: 305
Transmission: 700r4
Axle/Gears: Stock w/ 3.73 posi
Re: 305 TBI, won't idle and surges when runs
I'll backup the fuel pressure check idea. Could be a slit or hole in the short rubber hose that connects the fuel pump to the hanger assembly. Also, if you've solved the stumble issue yet still have weird idle problems, could be time for a new TBI flange gasket.
09-29-2014, 07:09 AM
#4
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Re: 305 TBI, won't idle and surges when runs
Muffler bearings...
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