Ok, I posted a week or so ago that my car had very little low end power (pulls weaker then my friends 81 Tempo under 3K RPM). After 3K RPM it starts pulling but then it shifts and loses the power again...

It is in no hurry to get to the 3000 RPM either. Now my car is an 86 TA 305TPI/700R4. I have checked the following things and while some fixed a little of the problem the main concern still stands:

New Plugs, Cap, Rotor, and Wires
Set Timing to 6 BTDC
Swapped in a good ECM with my PROM, same result
New Cat Converter

I am just about out of Ideas, this is what I can still come up with.

-Bad Oxygen Sensor
-Bad MAF (Either sensor, relay or connection)
-Bad TPS reading (Whats the correct reading? )
-Plugged up exhaust
-Timing still messed up (First time I used a Timing Loght, wasn't 100% sure I did it right)

Can anybody tell me which is the likely suspect since I really can't think of anyhting else and just might give up on the car. I am hoping to have some responses on possible fixes when I come home from school tomorrow so don't be shy...

Thanks for the help,
-Max

 

any of the ecm controls would set a code, did you check for any codes? i'd suspect the plugged cat.

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ICON Motorsports
1st & 3rd
MM Black Diamond 538 F&AM

 

No Codes from ECM consistenly, but once I got the TPS Voltage Code (22 I think) and MAF Burnoff Relay Code (36?). But after I reset ECM the codes didn't reappear.

I will take the cat converter off as soon as I get home and see how it runs without.

Any other suggestions, anybody?

-Max

 

I would think the cat is a good possibility.

------------------
"Rice burners are like tampons...Every pu$$y has to have one"
'86 IROC
T-TOPS, TINTED WINDOWS, BRAKE LIGHT BLACKOUTS
GM GOODWRENCH 350
EDELBROCK TES HEADERS
3" Hooker CatBack w/Aero Chamber muffler
EDELBROCK 600CFM CARB.
KN AIRFILTER
ACCEL HEI DISTRIBUTOR
160* Stat, just switched to 180* b/c of winter coming and going to college in the mts.
3:73 Posi
Rebuilt 700R4
B&M Megashifter, 5" Autometer Tach w/shift lite

 

I removed the Cat and still the sma eproblem. Under around 3K RPM it hesitates and stubles and then it straightnes out and pulls. So I'm looking for new ideas.

How likely is a pluged exhaust manifold or Y-Pipe. Also I'm thinking it could be a clogged fuel filter/failing pump. Anybody have anymore ideas???

-Max

 

A restricted exhaust would be more likely to cause a high RPM weakness than a low one. If you haven't replaced the O2 sensor in awhile, I'd start with that.

------------------
1990 IROC 350
Mods: Too busy trying to make it run right to mod it.
Airfoil, Dynomax cat-back, MSD coil, 180 t-stat, Bald Eagle tires,
Hypertech fan switch, Accel 23# injectors, Holley module, ported plenum,
Ported Daytona Yellow stock base, Moroso valve covers, other stuff,
Streetdampr, Ruger P95DC, hot wife, new oil filter, !cats, !TBC, !AIR.
18.0 @ 85MPH since I'm one big-a$$ MF
"It's better to have and not need than to need and not have."

 

i would check the TPS voltage. should be .56 volts i think

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- David
88' GTA 5.7L TPI MODS---> air foil, K&N, Shift Kit, 180* therm, TB bypass, Gutted CAT, Flowmaster 80 Series

http://www.geocities.com/david_angel_16

 

Will pick up a new fuel filter, a new 02 Sensor and will check the TPS voltage tomorrow. Keep the suggestions coming...

 

I had the same problem. Did you have your oil replaced or oil filter??? It took almost a week for the car to get all the power back, if thats not it, chekc ur plugs, the shop kept making my plugs tighter and i had full power for a minute or two, then it was gone again.

Hope this helps, i lost to my frinds 92 4runner because of this, very embarresing(i cant spell )

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1992 z28 25th Anniversary
All black w/ z28 wing
Flowmaster Exhaust
350 TPI

 

is all of this at part throttle or at full throttle... both??? fuel pressure ok??? ignition components ok (at least check plug color)...

zroc

 

I bought a couple of new things today. I gto an O2 sensor, a new fuel filter, some fuel injector cleaner (I know, I know don't tell me its bad) and a fuel pressure gauge.

I didn't have time to install anyhting excepot the FP gauge and when I start the car up I get 40 psi of pressure pretty constant throughout the RPM range. Is this normal or is this too low. Could this casue the hesitation I described?

Thanks for the help,
-Max

 

It's perfectly normal, so long as it increases some at WOT.

 

Is your rockers knocking.On my 2.8 the rockers were loose as he!!,car had same symptoms as yours. Last friday I took my valve covers off and adjusted them,and wadda know I have all my power back .Check your trans fluid level in all gears,that might help.Was a probelm with mine. Hope Ive helped, I just have to get the leak fixed on my trans and I can drive my car again.

[This message has been edited by 85SportCoupeto89RS (edited October 09, 2001).]

 

What does rockers knocking sound like, mine has a ticking/clicking sound coming from either the valve cover or the injectors. That sounds like an idea, I'll tkae off the covers this weekend if the situation doesn't improve.

 

They sound like someone hiting a hammer on metal.Depending on how loose the rocker is how loud the knock will be.

 

I figured it out!!! It was as stupid as a badly adjusted TPS!!! I adjusted it and now it revs nicely and idles nicely. Still vibrates but thats to be expected. As soon as I put the exhasut back on I'll take it out for a ride and will find out if the power is back