87 R10 w/350 TBI loss of power

[Bnjmnlthbry]

Hello everyone,
I have an 87 R10 with a 350 TBI that's experiencing a loss of power when I try to accelerate. I gave it a tune up not to long ago so I know that's not the issue. Anyways when I try to accelerate it will hit 2000 rpm and not want to go any higher. I use to be able to take off quickly when I wanted to but now my acceleration is pretty slow. Weird thing to is that I am able to maintain my speed after I get up there. So I am unsure if a bad tps or catalytic converter could possibly cause this. Furthermore if it's in park I can rev it up high no problem not sure if that matters or not though. Also it runs and idles great and it's only been doing this the past couple of days. So if anyone has any thoughts or ideas I'd appreciate it. Thanks in advance.

[zieg85]

Welcome to the site seeing this is your first post...  If it were me I would change the fuel filter.  Next would be check the fuel pressure. 

[bd]

Welcome to the site seeing this is your first post...  If it were me I would change the fuel filter.  Next would be check the fuel pressure. 

X2

Welcome from California.
We assume Service Engine light works and is not on with the engine running.

[Bnjmnlthbry]

Thanks for the welcome, we'll the fuel filter is new and the check engine light has come on a couple times but has stayed off since (It was only on for a few seconds). Furthermore the fuel pump is new forgot to mention that, but I will still check the pressure just to see.

[bd]

If the fuel pressure is normal and the filter isn't plugged again, here are a few questions to help us get better oriented:
* Did the low power problem begin before or after you replaced the fuel pump & filter? 
* Single or dual tanks? 
* When did the Check Engine light start coming on - what are the codes? 
* Stock engine & powertrain? 

[bake74]

      Welcome also from California.  The TPS could have something to do with it.  A plugged cat converter would not have these symptoms, it would cause back pressure through out the whole range of throttle, worse as the throttle is depressed more.(have you tried to bang on the cat to see if you can hear loose debris inside ?)
      Answer bd questions so we know more about your truck.

[Bnjmnlthbry]

I have banged on the cat and there is no sound also there aren't any unusual smells. I've heard that's also I symptom of a bad one. Also I won't be able to check the other things suggested until tomorrow since I'm out of town. I may just try changing the tps if everything checks out Monday.

[bake74]

     There is a test with a vacuum gauge to determine if you have a restrictive cat, but it does not sound like you have one.

[Bnjmnlthbry]

Well everything on my truck seems fine. The computer didn't store any codes either when the check engine light came on. From what I was told my truck has an early design that doesn't store them. So it's only readable when it stays on obviously. Also it seems to have come out of the problem completely. Hopefully its just a fluke, this truck had been sitting a while before i bought it, and not some intermittent problem that is brewing. Well thanks for the help and if anything does happen I'll be back.

[jaredts]

Never heard of a tbi that didn't store codes, but there's a lot I don't know.  Did you hear that from a reliable source?  Did you ground the aldl pins to try and check for stored codes yourself?  All you need is a paper clip or small probes with a jumper wire.  It was my understanding that if the light comes on you have a stored code unless you lose power to the ecm (unhook the battery).  If its gone that's great though.

[bd]

Glad to hear all is working. 

But, for your future reference, your '87 computer (ECM) does store trouble codes.  If there were no codes stored in memory after the Service Engine light came on, some of the possibilities are, 1) there actually were no faults, hence no codes, 2) battery power to the ECM was interrupted, 3) the Service Engine light came on because of no engine tach signal (code 12 - a volitile code that isn't stored), 4) ECM grounding problems, 5) wiring harness connection problems to the ECM, or 6) the ECM has an intermittent internal fault.

If you disconnected the battery after the Service Engine light came on, the ECM memory would have been erased.