[font size="1" color="#FF0000"]LAST EDITED ON 02-Apr-01 AT 08:13 PM (EST)[/font][p]Well ladies and gents...here is the problem. While accelerating the engine seems to lack power, then at around 1700-2000 RPM it surges as if getting a kick in the rear and runs fine throughout the remainder of the way up the RPM's. It does this in any gear at that RPM range, although while driving at around 40-45 mph in fourth or fifth the truck then hesitates as if running out of gas until you accelerate through this range. The following items have been replaced; fuel filter, spark plugs, wires, cap & rotor, air filter and tps sensor. The following have been checked and are in good operating condition; egr valve, air bypass valve, and pcv valve. These are just a few items as I am sure there are many others that can be checked. The vehicle in question is a EFI 4.9 Inline Six (duh) 5-Speed '94 F150 Ext. Cab Two-wheel drive w/131,467 miles. After reading some of the other postings here, how does one check for a faulty TFI? Also, am I crazy or are there two 'cats' on this dam factory exhaust system?


slim_vela

 

>[font size="1" color="#FF0000"]LAST EDITED ON 02-Apr-01
>AT 08:13 PM (EST)[/font]
>
>Well ladies and gents...here is the
>problem. While accelerating the
>engine seems to lack power,
>then at around 1700-2000 RPM
>it surges as if getting
>a kick in the rear
>and runs fine throughout the
>remainder of the way up
>the RPM's. It does
>this in any gear at
>that RPM range, although while
>driving at around 40-45 mph
>in fourth or fifth the
>truck then hesitates as if
>running out of gas until
>you accelerate through this range.
> The following items have
>been replaced; fuel filter, spark
>plugs, wires, cap & rotor,
>air filter and tps sensor.
> The following have been
>checked and are in good
>operating condition; egr valve, air
>bypass valve, and pcv valve.
> These are just a
>few items as I am
>sure there are many others
>that can be checked.
>The vehicle in question is
>a EFI 4.9 Inline Six
>(duh) 5-Speed '94 F150 Ext.
>Cab Two-wheel drive w/131,467 miles.
> After reading some of
>the other postings here, how
>does one check for a
>faulty TFI? Also, am
>I crazy or are there
>two 'cats' on this dam
>factory exhaust system?
>
>
>slim_vela
>

There are two cats on these engines. Get rid of the darn things and the engine comes to life. To see if there is anything wrong with the tfi do s systems check via the computer's diagnostics port. It located on the driver's side of the truck right by the firewall. You can either by a diagnostics computer from AutoZone or use a voltmeter to check the computers pulse codes. There is a website that shows one how to do this, but I can't remember the http address. If I can find it I'll post the address. I can't say for sure what the problem is. Hmmm.. let me think on this for a bit.
1994 Ford F150
300-6
Highly Modified and more to come!

 

Here is the site - has most other vehicles too _ just remove the "/ford.html" from the end.
http://www.batauto.com/Ford.html :-)

1990 F-150 4.9l 5speed 4x4

 

I had the same problem with mine before I yanked out the 300 in favor of an EFI 5.0! Turned out my entire problem was the cats, the front one came apart and plugged the rear one up solid! Which also lead to a messed up fuel presure regulator due to excess vacuum in the engine. Which just compounded the problem with the cats.

In short, get yourself a direct fit high flow cat setup. And you'll be happier, and so will the inspectors!


1988 F-150, SWB, 5.0 EFI (formerly 4.9 EFI), M5OD 5 speed, 3.08 gears, Summit shorty truck headers, Custom built Flowmaster exhaust system. Force 4 LP6000 lightbar, Federal signal PA-300 100 watt siren, Icom IC-V100 50 watt mobile radio.
=======================================
1965 F-100 (just purchased 1/18/01), SWB, 390, C-6 auto. Dual exhaust, Not much else to do to it.

Can see both below.

[link:www.geocities.com/hotrodford_88/|Hotrodford_88's Webpage]

 

Here is the latest...engine codes; 111...had the exhaust inspected by an exhaust shop...they say it is fine. I think my next step is maybe have the engine diagnostics done...yes?

 

After reading throughout the inline six series of messages I noticed a few others out there who had very similar problems as I am having now.

One in particular caught my attention and sort of got my curiosity going. It concerns the MAP Sensor...

After about $60 in tools (hand held vaccum pump w/guage and a good multimeter) I was able to diagnose a properly working IAT Sensor, EVR Position Sensor, and a faulty MAP Sensor. Yes that's right, it was a bad MAP Sensor. The computer gave no codes due to the fact that there was correct reference voltage, and a signal was being recieved. All be it the signal was constant (no change while applying 20hg of vaccum), it would not give a fault code. What I read is, the computer defaults to a pre-set back-up setting for the fuel/air mixture.

The fellow who posted the message concerning the MAP Sensor was right, this did wreak havoc on diagnosing the problem.

 

Part II...after replacing the MAP Sensor all seemed well and fine. WRONG, it still had somewhat of a hesitation although not all that noticable. Turns out the EGR Valve also had a leaking diaphram. Replaced the EGR Valve and the truck now runs like a champ.

Can you believe it...both bad!!! What are the odds?