MAP Sensor 1994 F150 XLT

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Dec 31, 2002 | 06:23 PM

eg0168

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MAP Sensor 1994 F150 XLT

Just bought this truck a month ago with 86k, paid only 4G and I thought I had a good deal(nice paint and body and very clean on the inside). Until I noticed some surging or tranny misses when cruising aroung 40-45mph and also sometimes at65-70mph. Very much dissapointed, went to my buddy to borrow scan tool and HE NOTICED the wiring harness attached to MAP SENSOR is missing and also the vacuum line. IS MAP SENSOR and vacuum is being used at all on this particular truck? and is this the one causing the problem?
(no codes shows up in scan tool)

thanks for anyhelp.

btw, also put plate restrictor on the egr but it doesnt help.

Dec 31, 2002 | 06:29 PM

steve83

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From: Memphis, TN

MAP Sensor 1994 F150 XLT

Sounds like someone tricked out the MAP, but I can't imagine why. I'd get a pigtail & sensor from a junkyard & splice it back in. If it seems to help but still has problems, buy a new one, but I've run my junkyard MAP for over 4 years now.

Dec 31, 2002 | 08:15 PM

Racerguy

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From: BC, Canada

MAP Sensor 1994 F150 XLT

Your truck probably has MAF instead of MAP. I've seen a few trucks that had a MAP installed but no wiring or vacuum hose to it.

Dec 31, 2002 | 09:15 PM

MustangGT221

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From: Topsfield, MA

MAP Sensor 1994 F150 XLT

He's got a 94 and he doesn't have MAF, it's speed density. If he has cali emissions he MIGHT have MAF but I still doubt it.

Primary rig is Green Thunder:
95' F-150 XLT 4x4, 302, 5 spd, MSD 6A, Flowmaster Exhaust, Sunroof, Clear corners w/ Diamond headlights, CD player with 2 10" subs and some 32" BFG Muds

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Justin - One Happy FTE Member

Jan 1, 2003 | 12:37 AM

Racerguy

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MAP Sensor 1994 F150 XLT

In 1994 the F150s were available with both MAF and Speed Density. Maybe California and Canada are different than anywhere else though....I'm not sure.

Jan 1, 2003 | 10:37 AM

eg0168

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MAP Sensor 1994 F150 XLT

If its not the missing MAP Sensor causing this problem. Do you guys think its the transmission? if so, how do i diagnose it.

Jan 1, 2003 | 01:55 PM

stevieray

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MAP Sensor 1994 F150 XLT

It could also be the EGR by-passing at off-idle. Try disconnecting the vacuum line and driving the truck fo a test. You will get a check engine light warning,but not to worry. It will go off nex time you start the engine with the hose reconnected. If it does improve the drivability, replace the hose and make a tin plate to put inbetween the Egr vale and the manifold to block the exhaust gasses from getting to the intake manifold. Another thing to try is the the 302 has the PCV valve routed to the intake runner for the number 8 cylinder. I found that there was an excess of crud being dumped into #8 and it was fouling the spark plug. Apparantly it can also ruin the piston, or so I have heard. I blocked off the hose barb on the manifold and re-routed the PCV to the center of the manifold where the Vacuum tree is. I had a very bad miss going up hills and this trick fixed the problem.

1993 F150 4x4clubcab 5.0/5spd w/31-10-15tires