rpm,s

[kvn4]

95 jimmy ,210850miles,4x4, 4.3 vortec While driving my tach shows 25000rpms as if gas pedal stuck. Have to pull over and shut off then restart to go back to 800rpms. Can this be the tps or am Iguessing.

[Chris Stewart]

Is the engine really running at 2500rpm?
Is it hard to stop as if the throttle is stuck enough to hold 2500rpm or does it idle normally and the tachometer not showing the correct rpm?

[kvn4]

it runs normal but after awhile it revs between 1100 and around 2500 rpms as if stuck. I smack the gas pedal and nothing ,but like I said only after driving for awhile .I tested the tps with dmm volts get blank between 3.5 and 5volts thats why the question.

[Chris Stewart]

Are you sure you had a good connection at the TPS?
Are the power brake vacuum hoses in good shape?
You should have a Check Engine light with a TPS code.
I'd replace the TPS first. Without the TPS, it might be trying to go on the MAP & Idle Air Control. Transmission shifts should be kinda kooky too. Is the butterfly tight on the throttle assembly.

[kvn4]

Chris Changed tps everythings fine now Thanks for advice. Mt code reader only reads 96 and newer obdii, will not read 95 obdii go figuire

[Chris Stewart]

Good! Glad it's fixed...kinda like a haint was on the pedal huh?
Yes the transition from OBDI to OBDII was a long, expensive transition for owners and general repair shops.
Each mfg had their own set of computer program/diagnostics that they didn't want out for the general public, creating a monopoly in which all repair work had to go back to the dealer.

To their credit, GM had the blinking Check Engine light code to help DIY's diagnose and kinda point you the right direction with a manual.

$50 to diagnose your check engine light to tighten your gas cap.
A lawsuit, by Snap-On I believe, put an end to it but while the court battle waged, GM developed seperate/hybrid programs for '93-'94-'95' before the lawsuit put all mfg's in line in '96 but now everything needed to be scanned with a purchased scan tool.
.....maybe the blinking Check Engine light wasn't so bad.

[kvn4]

hey chris , Back to square one . I changed tps,purge solenoid now it starts to rev to 1200rpms ,as it was in the begining sorry for faulse rpms,the throttle is closed when revving . Tap tps ,computer and still nothing.auto zone need pro diag as its a 95 obd11 and scanners give wrong reading because only gives codes for 96 and up .Any suggestions to what it can be now?

[Chris Stewart]

If it's slowly reving up with no slowing back, the Idle Air Control (IAC) valve may be sticking. It's mounted on the passenger side of throttle housing and opens & closes to control idle speed. Wiping the plug valve and inside the IAC seat with carburetor cleaner should unstick things.
I guess the Check Engine light is on too huh?

[kvn4]

sometimes when starting the rpms go right to 12000 and 15000rpms. I did have knock senser mal. as one of the origanal codes , problem seems to becoming more frequent. Shall clean (IAC) plug and such .Will let you know out come.