no power

[HOUNDLIFE365]

1989 ford ranger 2.9 4x4 idles at about 500rpm and will not rev above 1000rpm.
new parts: fuel pump ,fuel filter, fuel regulator, air filter, map sensor, tps, o2 sensors, iac valve, plugs, wires, cap & rotor
this really has me stumped and information would be greatly appreciated.

 

[CorbinsRanger]

Check your MAF sensor. and all the plumbing associated with it. Happened to me before. Engine was a dog. Had a spare maf and away I went. Hope you get going. Edit....did not see that you did the "MAP sensor....I'm guessing that is the MAF sensor. Sorry.

 

[Cees Klumper]

1. Vacuum leaks affect the engine/running a lot, so check for those - some of the connections on the intake manifold are hard to see and could just be wide open (blanking cap fell off for example). Check whether the brake booster is holding vacuum (basically it should be very difficult to pull the vacuum line from it). Also check whether all the vacuum lines are properly connected - some go before, some after the throttle plate. On my Bronco II a PO had swapped some of them which caused poor running as well as poor shifting of the automatic transmission.
2. Also check the fuel pressure to make sure it's at the right value
3. Check the spark plugs' firing order
4. Proper ignition timing (spout connector removed when setting the timing, put back when done) is important also - I know this one is obvious, but I forgot to do this once with the spout connector removed and it ran really badly.
5. Check for codes - OBD1 reader
6. You did not mention the ignition module 'TFI' on the distributor, those go bad and this could well be your problem
7. Try a replacement computer - they can also go bad (oftentimes they just need replacing two $0.50-$1.50 capacitors, not that difficult to do). Very coincidentally, just tonight my 240K miles '90 Bronco II failed to start up - it started, died immediately then would not fire back up, and the 'check engine' light started flickering strangely. I swapped in my spare computer and it fired right back up and is running perfectly again. This happened to me about two years ago, same issue, on the original computer. One morning it just would not start (although a few hours later it did). I got the extra one off Ebay for around $100.
8. Lastly (since its the most work - but still quite do-able for the shade tree mechanic) - try replacing the fuel injectors with properly rebuilt original ones - on my this was the single most significant improvement in the engine I made. I spent $60 on a set of six a few years ago (Bosch), they are a bit more costly now ($100-150 for the set? Check Ebay), but get the properly rebuilt ones and it's well worth it.

New parts try and get Motorcraft, your best bet for quality. Other brands can be 'bad out of the box'.
Good luck!

 

[Eddo Rogue]

What they said.

 

[RonD]

Engine is a self powered air pump

No pump can work well if it has a blocked intake or a blocked outlet

So check air filter and path IN, and Exhaust OUT, clogged muffler or Cat converter

 

[rusty ol ranger]

Did this issue start all at once, gradually, or after changing parts?

Id buy a vacuum gauge and use it to check for cat restriction.

I would also pull codes and see what you come up with.