Did I break my truck?

[Richard Jones]

95 C1500
5.0 305

Help!

Lol OK so here is what's going on. I have had a constant high idle that is 1000 at start up then after driving it is consistently around 1300-1500 at idle. This all started few weeks ago, since then I replaced PCV and hose, no change. Replaced iac, no change. This morning I replaced throttle body base gasket, at start up it idles 1500 immediately, when I give any gas it bogs down immediately, when I shut it off I hear a loud screech coming from somewhere... What did I do wrong? I need to get it at least in the shape it was in prior to replacing gasket. I am not a mechanic probably should've gotten help with this but have done more difficult things successfully on my own. I'm stumped.

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[kennythewelder]

Ok the first thing you need to do is get the codes from the ECM.If you don't know how to do this, just look on U tube. You may have a TPS issue. Also you may have a vacuum leak, but the ECM codes will not tell you this. You can check this with a propane torch ( like the little one you buy at Lows ) and open it unlit over the vacuum hoses and connections. If there is a leak, the engine will d]speed up when it sucks in the propane fumes.

 

[skylark]

You can also use carb clean to find vacuum leaks.

 

[joep88cheyenne]

TBI gasket would have corrected the fast idle if it was the issue. A screech is slipping belt most likely. Check the throttle to see if it is not coming to rest completely, or if it is sticking slightly open. If so need to correct it.

 

[Richard Jones]

Ok the first thing you need to do is get the codes from the ECM.If you don't know how to do this, just look on U tube. You may have a TPS issue. Also you may have a vacuum leak, but the ECM codes will not tell you this. You can check this with a propane torch ( like the little one you buy at Lows ) and open it unlit over the vacuum hoses and connections. If there is a leak, the engine will d]speed up when it sucks in the propane fumes.

Thank you man I really appreciate it. Never knew about this. Thought I needed a scanner. This should help narrow my problem down.

 

[Richard Jones]

Pulled the two codes

22-TPS circuit low
33-MAP sensor circuit high

So does this mean both sensors need replaced or is there another reason for these codes?

 

[89RCLB]

Troubleshoot one problem at a time...there is a ton of "how to" information on the internet for testing a TPS.

 

[kennythewelder]

Replace the TPS first, then dis connect the battery for a few mins. to reset the ECM. Run the truck for a little while 20 30 mins ( go test drive it ) Then pull the codes again. If the code 33 is back, then replace the MAP sensor, and repeat the battery disconnect trick, and run test run, then pull the codes again. This should fix up your issues, lest hope anyway.

 

[Richard Jones]

Replace the TPS first, then dis connect the battery for a few mins. to reset the ECM. Run the truck for a little while 20 30 mins ( go test drive it ) Then pull the codes again. If the code 33 is back, then replace the MAP sensor, and repeat the battery disconnect trick, and run test run, then pull the codes again. This should fix up your issues, lest hope anyway.

Thanks I bought both will just replace both and reset and hopefully test drive if this brings it back to driveable. I'll let you know if problem is solved. If so I owe you big time

 

[Richard Jones]

Replaced both sensors... No change. And in the process found this plug and don't know where it belongs? Still idling very high and seems like its not getting much fuel and has a loud air sound.

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