I've had a frustrating and annoying problem for a while. Here's what it does, it stumbles, hesitates and bogs bad...but...only 1500 RPMS and under. I've replaced every hose in sight, changed every filter i could find, changed routine matenance stuff like cap & rotor, plugs, plug wires, etc. Still no change.. I was reading a post the other day on a BAD TPS. The guy said his car wouldn't idle below 1500 rpms, etc, which is what mine does, and with the slightest touch of gas it'll start going but any more than that it acts up. Doesn't wanna idle smooth at all, idles rough like it has a monster *** cam. I just dunno if its that or my fuel pump, or maybe both? my fuel pump used to prime in the morning when i'd turn the key 'on' but not anymore...dunno what gives.

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89 IROC-Z 350 TPI

-Flowmaster Catback
-Performance Resource Chip
-700R4 (Rebuilt) Too much done to actually list
-K&N Airfilters
-Ported Plenum
-2.77 Gears (not much to brag about but eh, its there)
-Future:
-383 Stroker?

 

Reset the ecm (pull the fuse under the dash for 60 seconds) and see if it throws any codes. Go through the procedure to check even if the light doesn't come on. Maybe that will tell you what's wrong. It wouldn't hurt to reset your IAC and adjust the TPS anyway. While you're doing that, get a non-digital voltage meter and observe the sweep of the arm as you open the throttle. If the TPS is bad you will see it hesitate and pause as it moves upwards. If the TPS is good it will move in a smooth arc.



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87 IROC-Z, 5.7, auto, 3.27, leather, !cat, Holley fpr, K&N'S, SLP 1-3/4" Jet-Hot coated headers, SLP .218/.224 .495/.502 cam, Comp 1.5 roller tip rockers, $uperPITAram, Edelbrock lower intake, Holley 52mm tb, Dynomax\Flowmaster catback. Coming Soon(?)- Fasttrack/Accell DFI

1989 Pontiac 20th Anniversary Turbo Trans Am - 160,000 miles, K&N filter

 

i adjusted the IAC, and re-adjusted the TPS, still no difference...one thing i noticed with the digital meter....at WOT no volt reading?

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89 IROC-Z 350 TPI

-Flowmaster Catback
-Performance Resource Chip
-700R4 (Rebuilt) Too much done to actually list
-K&N Airfilters
-Ported Plenum
-2.77 Gears (not much to brag about but eh, its there)
-Future:
-383 Stroker?

 

Branz,

Zero volts at WOT can only mean your TPS is failing, or the connections from your meter are falling off every time you go to WOT. If you're sure you're connected properly, the TPS might be toast.

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Later,
Vader
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"Make Me Bad"
Adobe Acrobat Reader 4.0

 

I'm gonna add to the confusion, today i ripped everything off that i could (injectors, fuel rails, etc) put it together..and i saw a connector loosely hanging (harness) i left it unplugged and put my car back together, then tried to start it. Started but no temp reading? the sensor i guess is nearly directly down from the throttle body. when i removed the connector it has 2 prongs, what sensor is it? also, while my car is cold it acts fine for a little while then acts up...what would cause that...like maybe the first 1 or two shifts are fine, goes to 2000 rpms...boom..does it again...and then it doesn't want to co-operate...wants to do its own thing...heh I replaced the tps today...no help...better idle....better take off but something else has to be causeing it...also...it revs slow, very slow and trys to bog with more than the slightly ease of gas....around 4,000 rpms it acts like it can't go any further.... oh ya, this also happened like a week or less after i ported the plenum and portmatched the runners. Would that have done anything? From my understandings the MAF is rather flexible on air modifications. Could it have fooled my computer into thinking its at more throttle than what it really is?

------------------
89 IROC-Z 350 TPI

-Flowmaster Catback
-Performance Resource Chip
-700R4 (Rebuilt) Too much done to actually list
-K&N Airfilters
-Ported Plenum
-2.77 Gears (not much to brag about but eh, its there)
-Future:
-383 Stroker?

[This message has been edited by branz28 (edited November 19, 2000).]

 

Bran, My car does the Exact same thing.
I have narrowed it Down to the TPS, Ill replace it soon Enough here.

Glad to Know someone else feels My pain


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85 Z28 - Daily Driver
60 Ranchero - Project ( Money Hole )

 

The sensor you're talking about is the MAT sensor. It needs to be plugged in, but has nothing to do with the temperature gauge. The temp gauge sending unit is right next to the #1 spark plug on the driver's side cylinder bank. Check if it's connected.



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'88 IROC 305 TPI
Gutted airboxes
160 degree T-stat
Advanced base TPS voltage
Relocated IAT sensor
Momo steering wheel
Ram-air setup coming soon
Flowmaster muffler
Taylor SpiroPro wires
Accel cap and rotor