I have 1988 Chevy G20 with a L05 350 TBI, will start 50% of the time, idle is extremely erratic, it will not stay running most of the time, If i do get in gear and moving it surges and bucks alot, has occasional backfire through the intake when under load or uphill. It has no power. the timing is correct, fuel pump and filter are new, fuel is coming out of the injectors. fuel psi is at 10. new cap and rotor, new plugs and wires, new tps, neew o2 sensor, new catalytic converter, new fuses on everything. I drove it 20 miles with no problem and later that afternoon it went to crap. what could it be?

 

i had a 1990 silverado with a TBI 454, i had a very similar issue. and i was like.. my 454 has no power!!!!!! LOL was i WRONG!!!

it turned out to be a "TPS" (throttle positioning sensor) and was a couple hundred dollars.

could be something to look into and or consider.

the truck ran phenomenally after it was replaced and had LOADS of POWER!!


hope this helps.

steven7685

 

thanks, Ive replaced that and it still has the same problems

 

Have you looked at the EGR valve?

 

nope, not yet, how can you tell if one is bad?

 

Baker read his original post,,,, I beleive TBI is throttle body injection.

As to checking EGR reach behind it and pull up on the diaphram thru the holes this should cause the motor to run rough, if it doesnt the port could be plugged with carbon. If it makes a difference try hooking a vac source to it to see if it operates.

 

We re on the same page. I was going to say this also. A pintle partially stuck open could give you all those symptoms.