Lack of power when warmed up

[Agentchuckles]

Hey guys...i put a speed density 302HO from an 88 notchback in my toyota 4runner monster truck this summer. I seem to have a problem with it. It runs great with lots of power when it's cold. As soon as it gets up to temperature...it seems to lack power. I can give it throttle and it seems to rev...but doesn't pull at all.

If i floor it...then it seems to all of a sudden get some power, but not as much as it should. It sometimes backfires too. Also when it's cold..and i start it..if i lay on the gas to rev it, it'll back fire and lean right out and stall. I have to slowly rev it and then i can blip the throttle after it's been revved slowly.

I've plated off the egr port but haven't done the resistor trick to the harness connection yet. Not sure if that's it.

Anyone have similar experiences and find the cure for it?

Thanks

 

[Black1987Stang]

Pull codes?

 

[jrichker]

Dump the codes and see what the computer says is wrong…

Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great.

See http://www.troublecodes.net/Ford/
OR
See http://www.mustangworks.com/articles/electronics/eec-iv_codes.html

IF your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.

Codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.

Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.

For those who are intimidated by all the wires & connections, see http://www.actron.com/product_detail.php?pid=16153 for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Walmart.

Or for a nicer scanner see http://www.midwayautosupply.com/detailedproductdescription.asp?3829 – It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $35.

 

[Synned]

I have the same problem...still haven't been able to come up with anything.
New cap/rotor/wires/plugs/maf/o2s.
But I needed those items for a tune-up anyway. When the car is warm I seem to have absolutely no low end at all, like its just completely missing. I can burn out great when its cold, when its hot forget it. It takes a lot longer in the winter.

 

[Agentchuckles]

Ok guys...i pulled the codes today.

23 - possible bad tps?

31 - egr has been removed but the connector left open

67 - air conditioner clutch switch? i have no a/c...except with the windows down in winter.

81 - Thermactor - removed and connector left dangling.

82 - Another thermactor code

84 - EGR control circuit.....again...EGR removed

85 - Canister purge circuit. Hmmm...it's not hooked up yet as i'm leaving my gas cap off to vent the tank for time being. The purge solenoid has a busted nipple on it so i'll have to pick up a new one eventually and hook it all up. Connector dangling for time being.

Could it be just a bad tps? or one needing adjustment per se? I played around retarding the timing a bit...but it started running with no power at all...no pull or anything and backfires under load as well with multiple pops in the intake. I wonder if i've got a worn cam/lifters. I'll do a compression test tomorrow.

Any ideas?

 

[HISSIN50]

Do you hear any pinging when it runs like poop?

 

[90mustangGT]

Some reason I'm leaning towards the TPS or MAF issue.

 

[Agentchuckles]

i dont' hear any pinging. I do get a good pop from backfires once in a while while accelerating under load. When it's cold...i can chirp 38.5's with my crappy 4.10 gears and auto trans (th350 adapted) from a takeoff and it accelerates real nice. When it warms up...Its almost like it's leaning out until i give it full throttle and manually shift my auto down to a lower gear and it picks up...sometimes fast...sometimes mediocre...but from 1/4 to 3/4 of throttle...gutless. I know a bad tps can cause it to fall on it's face during a certain throttle range so i might try changing it. It woudlnt' be a MAF issue as my 89 engine is speed density. Could disconnecting the EGR valve and not tricking the EEC with resistance at the connector be an issue?

Thanks
Tony