Fuel Pressure/Idle Issue

PittSpeed Automotive
1

Ok, so my 87 Suburban is a TBI engine setup. A couple of weeks ago, as it was getting warm, I noticed that once the engine was warmed up it would tend to idle REAL low at stop lights, around 500rpm, and every once in a while it would stall out.

It did this last summer as well, but once winter time came, it quit. Hasn’t done it since then until just now.

I figured it was one of three things…

PCV valve
EGR valve
Fuel Pump (or some other fuel related issue)

I replaced the PCV valve and it made absolutely no difference, still the same issues. Today I replaced the EGR valve and the truck seems a lot more steady during idle, will not idle down or anything when I’m sitting with it warmed up and in drive, but when I go to hit the gas, it will bog for a half second, then rev up to 1500 or 2000rpm, then bog again, then go back up. It will do that 3 or 4 times then be fine until I get to a stop sign or light, then it will do it all over again.

I’ve got a feeling my fuel pump is going. Is there any way for me to check the pressure I’m getting on here? Also, is there a chance its a regulator issue instead, or maybe an issue besides the fuel, something completely different?

Any help is wonderful.

2

maybe its a sign to LS1 it…:smiley:

3

TPS - sounds like it could also be the throttle position sensor. My S10 was exhibiting close to the same behavior as you have described (wanting to stall/very low idle speed). Only did it in warm summer weather. Was really bad after a cruise on the Turnpike. I waited until it got bad enough to set a code, went to AutoZone and had them read it. It was the TPS. $35 and about 15 minutes to change it out. Completely fixed it.

4

Yeah I changed the IAC last summer thinking that might be it, then it got cooler and went away and I thought it was fixed. I guess it could be the TPS. Thanks for the suggestion.

Anyone else have any ideas?

5

before you go spend the money on a TPS , check ur current one with a multimeter

6

Well, after cross-checking the number on the original EGR valve with the new one, I believe that AutoShit gave me the wrong one. I’m going to go back tonite and exchange it for the one that I need and see what I can do from there.

Thanks guys, I’ll post back up if this solves the problem(s).