91 chevy tbi motor not runnig right.

[73chevytruck]

My truck started to do this thing where it seems like its missing. And won't rev up. But then if I put the pedal to the floor it will clear up and rev up. I relaced the cap and rotor. Wires.plugs and fuel pump a few months ago. Anyone know what it could be I was possibly thinking fuel presuure regulator insidie the tbi?

[Ranger Dave]

is therre any check eng lights on. 

could be oxy cencer ,

could be modulater in dist.

take it to advanced auto and  have them plug it into ther  code reader. or  bring it over here steve  i have  a code reader for that truck.

[burl]

Tps?

[Jr]

coolant temp sensor

[OHEARN.2012]

coolant temp sensor..

[73chevytruck]

I swaped in a whole other distribitor with a new ing modual. And it has a brand new coolent sensor. And yes the check engine light does come on. I used a paper clip to pull the codes and then looked up what I got and it said vss low signal. But the trucks been doing that the whole time it had it and the problem just started about 2 months ago then I put in a new cap/rotor. New plugs and wires. That didn't help so then I swaped in a new distribitor. That didn't fix it so last Friday I went and put a new coolent sensor in it the one next to the thermostat housing.Both injectors are squirting fine.when it starts sputtering if I put it in neutral and rev it up real quick then put it back in gear it will run fine for a minute. Then start doing it again

[ToughBowtieTruck]

VSS low signal is just the vehicle speed sensor, related to the transmission and speedometer. If it acts like it's flooding out see if there's black smoke out of the exhaust. Then it's probably the fuel pressure regulator. That and a gasket overhaul kit for the TBI can be had for around 60 bucks or so. Makes a difference rebuilding the tbi vs. throwing another used one on.

[73chevytruck]

Yea advanced auto has a bwd tbi rebuild kit for 25 bucks with the fuel pressure regulator in it. Going to get it tomorrow and see if that fixes the problem

[91 k1500]

there is two coolant temp sensors on the tbi engines just an fyi... one for the ecu and one for the gauge..... look at the left cylinder head by the exhaust manifold.... also check to make sure that the egr valve is not sticking....

[old school truck dude]

Advance and autozone say its too old for their scanners, is what they always told me.. If itll rev when you floor it, it really sounds like its floodin, I think Bowtie is tellin ya right on rebuild the throttle body. This is guesswork, this internet diagnosis, but if theres no codes other than vss, it might just be that Oh yeah, and just because somethin is NEW, dont mean its GOOD. I fought a bad o2 sensor for 4 months on my S-10, 3rd one finally worked right! Gee thanks, Autozone! Buncha junk.. 

[73chevytruck]

Ya I bought a tbi rebuild kit tonight going to put it in tomorrow after work and see if that helps. If not gonna pull the tank and replace the pump again scince its lifetim warrentiy lol.  And the check engine light has been coming on for the vehicle speed sensor scince I got runnig after swithing it over to tbi and it was running right at one point lol

[73chevytruck]

I rebuilt the tbi. And no change. I'm going to check out the egr valve tomorrow.

[RIP_K52007]

pull a vacuum on the egr and see if it changes, if it dont it means the egr is stuck open.. if it does then its probably fine. It could be stuck partially open but mine have always stuck all the way open, all the way shut or worked fine. The sonoma blows a hole threw the EGR base gasket every year..

[73chevytruck]

Well my egr valve is working I can move it byy hand and it will go back. Guess going to try a tps sensor next.

[RIP_K52007]

tps should technically only affect it in one general spot... cause they just get burned out spots inside where cruising speed and idle are at.

[bmwallace_88]

does the truck have cats on it? might be plugged? i know my thunderbird when the cats plugged it ran alot like this.

[73chevytruck]

Nope no cats and true dual exhaust

[old school truck dude]

Well my egr valve is working I can move it byy hand and it will go back. Guess going to try a tps sensor next.

You can have a big fat vacuum leak right there at that thing even if it moves and stuff. I had alotta trouble with mine, had to dig down in there and get all the carbon out best I could, new egr and it ran great after that. Seems like they dont usually act up in the same way every time, like its always a guessing game with these and ya gotta have spare parts to try on hand lmao

[ourlittleranger92]

Did you convert your O2 Sensor to a heated one? we did that on my buddies 91 and it made it run like how yours is sounding.

[73chevytruck]

Nope still got the stock one in. Gonna mess with it more and see if I can figure it out.