have an 88 ranger with power loss

[mofo93]

I Have an 88 ranger that's been giving Me problems but finally got it runing and idleing fine till I turn on heater headlights radio ect then idlidle drops little by little till it chokes itself out recently changed fuel pressure regulater fuel filter iac valve o2 sensor any help would be greatly appreciated

 

[kevinbmx77]

I had this issue too and for me it was the fuel pump, i was able to drive but when trying to accelerate the truck would not pass 3000 rpm. I spent alot of money on other parts that didnt help before i tryed the fuel pump.

 

[mofo93]

I've figured out last night that if my ac/heater is off it will run great but as soon as you kick it on with any lights on it drops the rpms down by500 and starts choking itself out

 

[RonD]

The IAC(idle air control) Valve doesn't seem to be working.

Fuel injected engines don't have Jets so an idle screw doesn't work well.
So the IAC valve is used on all fuel injected engines
Computer gets RPM from distributor/coil, or CKP(crank position) sensor, it has "target" RPMs in memory that it tries to maintain using the IAC valve.
Cold engine idle should be above 1,000rpm, colder temp = higher RPM
Warm engine idle should be 700 for manual trans, 800 for automatic
As you turn on accessories, engine load increases so idle drops, computer sees this and opens IAC Valve a little to compensate.

IAC valve is fairly easy to remove and clean as a first step
It is a motorized valve on the upper intake, it can get dirty inside and valve sticks.

Computer tests IAC Valve on cold starts and some warm starts by opening it all the way and then closing it to "target" RPM level, if your idle doesn't go high, above 1,500rpms at first startup, and then drop, it could have a bad connection or bad motor.

 

[freedom5]

Could be a drop in voltage to the fuel pump due to a corroded or faulty Fuel Pump relay. I had similar problems until it finally failed to start. I found the fuel pump relay full of corrosion. Cleaned the contacts and replaced the relay and now it starts, accelerates and runs like new. You can by pass the relay by jumping the relay wires # 3 & # 4 which will by pass everything and apply power directly to the pump. The key doesn't have to be turned on. If the pump is good you will have pressure to the fuel rail. PSI should be 35 - 45.

 

[Derf_the_Mule]

Check your alternator with a mechanics stethoscope (or long shaft screwdriver up to ear) it could be bad alternator bearings. This is cheap and fast and can eliminate/diagnose a bad alternator. Take a look at the connectors as well and see if they are corroded. A bad water pump can do that too. Listen to it as well if you can.

Bad battery connections can show as electrical problems, as well as corroded relays, etc. Check the neg cable that enters the lead clamp by wiggling and pulling (don't remember when copper clamps started, disregard if copper) I had one corrode between the copper wire and lead clamp.

Have your battery tested if you can to rule that out as well. Most part stores will do it for free. A bad battery can overload your alternator easily.