Codes 87 and 95 dies intermittently with high idle

[Epalm18]

Hello, I have a 91 Ford Explorer 4.0. Vehicle sat for a year and leaked water down to the computer. Replaced computer and then ran good. However, it only makes it about 15 miles then CEL comes on, loses power, idle ramps up to about 2 thousand RPM on side of road and dies once I give it some throttle (otherwise it will just sit there at about 2 thousand rpm until I kill it). Fires right back up runs great then later on down the road it does it again. It’s done it every time I’ve drove it now. It also seems to have an extended crank when cold. The 2 codes that are present are a 95, and an 87. Things I have replaced include: fuel pump, canister purge valve, throttle positioning sensor, computer, fuel filter, spark plugs, plug wires, fuel pressure regulator, water pump, thermostat, fan clutch, and radiator. I also made sure fuel cutoff switch was good. Please help! Any suggestions welcome as I am stumped and tired of throwing parts at it thank you!!

 

[Rick]

Code 95 is fuel pump circuit issue.
Code 87 is fuel pump circuit intermittent.

I would check the fuse/relay box for corrosion on the backside of the plug ins, and also recheck your connection at the fuel pump.

 

[Epalm18]

yep did that yesterday. Replaced fuel pump relay while I was there. Good connection at pump. Any other ideas?

 

[Rick]

All I can suggest is to get a hold of a wiring diagram and start testing the system from end to end with a VOM looking for voltage drop, bad grounds and intermittent connections.

 

[Epalm18]

that’s what I was thinking. Okay sounds good thank you a lot

 

[Roadrunner777]

1 - Getting those codes and having proven out everything external on the fuel pump circuit, it could be that the computer you purchased (which I assume is used and therefore 19 years old) may have one or more bad capacitors. They can fail as they warm up, and the timing sounds about right. The computer would pass a bench test on a 1 minute test, would seem to be working if they pulled it from a car headed for the crusher.

2 - The wild idle thing reminds me of a failing MAF, loose connection, something along that line.

These may be related. The bad capacitor may be in the section that conditions the signal from the MAF. There are voltmeter tests for the MAF itself. Bad capacitors, you basically have to open it up and see if any of the little cans look odd, leaking, bulging, etc...

 

[Epalm18]

yeah I’ve been wondering bad computer. It was one I purchased off rock auto that obviously is remanufactured. Will look into mass air flow. Thank you!!

 

[Epalm18]

Also, does nothing when I unplug MAF. Still runs fine