1998 Explorer problems

[anitadupont]

I hope someone can help me. I just recently got a 98 explorer 4.0 V6 single overhead cam and I am having all kinds of issues. When I picked it up and started driving home it started acting funny, stalled at stop signs, stalled while driving, hesitated from a stop and the check engine light came on. Took it to advanced auto the did a code reader and said the two O2 sensors before cat converter need replaced. So I replaced them. That did not help then all kinds of other codes came up. Here is a list of what has been replaced:
two O2 sensors before cat converter
spark plugs
IAC
TPS
MAF
CAT Converters
2 fuel injectors 1 and 3
air filter
fuel filter

I think that is everything that has been changed

Did another code read and most of the same codes came up - Fuel rich Fuel lean misfire 1 and 3

This is what it is doing now:
spuddering
backfiring
hesitating from stop
reving up on its own when driving
when you have the cruise set it will rev up about 5 mph slow back down then rev up again

I hope someone can help me.

Also they said motor and tranny had been changed. There was a tag under the hood from ford saying it was reprogramed in 2005

 

[joecrna]

Id say IAC but you replaced that. So now I would say vacuum leak. Are the codes all from the same bank on the engine. The misfire could be wires too. All the other codes, O2 sensors, cats are ery likely a result of something upstream and not really those items themselves.

 

[Joe Dirt]

I would also check the intake gasket for leaks, since the motor was probably apart.

 

[1Aauto]

welcome to the site

 

[anitadupont]

Changed the Gaskets and egr valve and still has the same problem backing and shuddering / jerking. Very frustrating. Don't know what else to do.

 

[2000StreetRod]

Post the codes

It would be helpful if you posted the current actual malfunction codes.

It is unusual to have both too lean and too rich codes.

I suggest that you recheck the plug wire connections for the correct firing order. The photo below was posted by janolsson:

It's common to overlook that 5 and 6 are swapped on the coil pack.

Sometimes the crankshaft position sensor causes misfires. You can clean the contacts by disconnecting and reconnecting the electrical connector a few times. Being located low on the timing cover exposes it to water, dirt and road tar.

 

[anitadupont]

Thank you guys oh so much for all your help. Ok these codes came up before P1151 P1132 P1152 P0113 P0172 P0175 P1131

Well yesterday here is what codes I got from Autozone:

P1152
Definition
Lack of O2 switches - bank 2 sensor 1 - rich

Explanation
ECM detected O2 at is rich limit

Probable Cause
Fuel rich high
EGR stuck open
Engine mechanical condition

P1131
Definition
Lack of bank 1 O2 transitions - lean

Explanation
ECM detectec bank 1 O2 at its lean limit

Probable Cause
Misfire bank 1
Vacuum leak affectingf bank 1 only
Fuel injector problem bank 1
Engine mechanical condition

P0172
Definition
Fuel trim bank 1 condition

Explanation
The power train control module uses the oxygen sensor to calculate the Air/Fuel ratio of the engine. The computer reconized a rich or lean condition on one engine bank only

Probable Cause
If bank 1 and 2 codes set together suspect fuel pressure of MAF sensor
Oxygen sensor defective
Ignition misfire - repair
Fuel injector problem

P1506
Definition
IAC overspeed error

Explanation
ECM has detected and engine speed greater than desired

Probable Cause
Engine vacuum leak
Failed IAC valve


I don't know what else to do. This morning it fired right up let it run for like 20 mins. Sometimes it acted like it was gonna stall out (but didn't). It would rev up a little then back down.

GRRR my truck is driving me crazy.... When I take it somewhere they act like I don't know what I'm talking about and keep telling me the problems that I have already replaced.

 

[joecrna]

Still sound like vacuum leak to me. The question is where. You said you have changed the EGR valve, check the metal tubing too. If thats OK check the PCV valve especially the elbow, it often cracks and can be very hard to see until removed. Then search the intake gaskets for vacuum leaks.

 

[2000StreetRod]

Fix IAT sensor first

P0113 Intake Air Temperature Circuit High Input

P0172 System too Rich (Bank 1)

P0175 System too Rich (Bank 2)

P1131 Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Lean - Bank No. 1

P1132 Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Rich - Bank No. 1

P1151 Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Lean - Bank No. 2

P1152 Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Rich - Bank No. 2

Your intake air temperature sensor was probably damaged or not properly connected after the MAF sensor was replaced. It should not have enough effect to cause your more significant problems but I suggest you fix it first to eliminate confusion. I think the IAT sensor is separate from the MAF sensor on the 1998 models.

Since you have no misfire codes I doubt that misfires are causing your too rich codes for both banks. Make sure that your intake system is not clogged/blocked.

Does it sputter more or less for engine cold starts?

Did you recheck the spark plug wire routing?

 

[2000StreetRod]

Why too rich?

I assume that your vehicle is a stock configuration with no intake, PCM or fuel system modifications.

The diagnostic trouble codes (DTCs) indicate that the O2 sensors are detecting excess unburned fuel in both banks and the PCM is unable to reduce the fuel while staying within normal operating parameters. The PCM relies on the MAF sensor output voltage to determine the intake mass air flow and calculate engine load. If the MAF sensor is defective or the sensor element is contaminated the reported air flow will be inaccurate and the PCM will implement the wrong fuel mixture (injector pulse width). If the MAF sensor output is outside of normal limits the PCM will set a DTC (P0100, P0101, P0102, P0103 or P0104). Since you have replaced the MAF sensor and have no associated DTCs I will assume that it is operational. To test the MAF sensor: MAF Sensor Test Procedure

The PCM relies on the throttle position sensor (TPS) output voltage to determine desired engine performance from idle to wide open throttle (WOT). If the TPS is defective the PCM will not be able to anticipate desired performance. If the engine is slowly accelerated it will not falter because of the MAF sensor readings. However, if the throttle is rapidly changed the engine will falter. If the TPS is outside of normal limits the PCM will set a DTC (P0120, P0121, P0122, P0123 or P0124). Since you have replaced the TPS and have no associated DTCs I will assume that it is operational. To test the TPS: TPS Test Procedure

The PCM relies on the crankshaft position (CKP) sensor to determine engine speed and ignition timing. A defective CKP sensor often results in cylinder misfire DTCs (P0300 thru P0306), engine speed input DTCs (P320 thru P0323), and CKP sensor DTCs (P0335 thru P0339). Since you have no CKP sensor associated DTCs I will assume it is functional.

I suspect that unmetered fuel is entering your intake system and it is not cylinder specific. Apparently someone else suspected a fuel problem since injectors #1 and #3 were replaced. One possible source is a defective fuel pressure regulator (FPR). You have a return type fuel system. The FPR on the fuel rail varies the fuel pressure to the injectors based on engine load (vacuum). At idle when vacuum is high fuel pressure is low and at WOT when vacuum is low fuel pressure is high. If the vacuum hose from the intake manifold to the FPR is split, broken or disconnected then the vacuum will be low and the fuel pressure will be high causing a rich condition. If the hose is in good condition but the diaphram in the FPR is ruptured then fuel will leak past the diaphram and be drawn into the intake manifold via the vacuum hose. I suggest that you remove and inspect the FPR vacuum hose. If it contains fuel then replace the FPR. If it is split or broken then replace the hose. To test the FPR: Fuel pressure test procedure

 

[anitadupont]

Ok....I am still having problems, but husband thinks its the PCM I just got another one but I need to get it programed. Do you guys think that could be the problem?

again here is a list of my problems
Backfires
sometimes stalls out when running in the driveway
sometimes stalls out when at a stoplight
when I take off from a stop it doesn't move, I give it gas nothing I let off the gas then give it gas....i do this like 10 times then it catches and goes
but then it slow down and I have to do that cycle of events all over again.
when driving on the highway at a stead speed (even with the cruise control on) it will all of a sudden increase speed by about 5 mph then back down to what speed I am set at
it will stall out while driving, I put it in neutral and it starts back up
RPM are running higher than normal now

 

[joecrna]

You say you have a new PCM. Then changing it out wont hurt the truck and will help your marriage. Have your husband do this now. I doubt it will fix any of your problems but they do go bad occasionally. If Im right, no harm. You've already spent the money getting the new one. If Im wrong, great! Your husband just fixed your truck. Reward him appropriatly. Just speaking from a bit of experience.