1986 928 erratic idle and performance, what are some things things to check?


Asked by Jun 09, 2012 at 09:27 PM about the 1986 Porsche 928

Question type: Maintenance & Repair

My 928 is stalling, and driving bad. It has 108K miles and in good shape. The relays were replaced.

4 Answers


This must be a k jetronic fuel injection system, if it is clean the plate with a carburetor/injector cleaner also clean the idle valve and throttle plate. Check everything regarding maintenance spark plugs, cables, rotor, filters etc and test the car. Generally this system has this issue

1 of 1 people found this helpful.

Hello Hector, The car has teh LH system with the MAF, is this what I need to clean? I removed the air filter and some leaves from the MAF screen. You say to spray that intake with carb cleaner? I will check the plugs and wires too. Where is the idle valve located, and the throttle plate? Thanks for your advice. Tony

1 of 1 people found this helpful.

Ok, not spray, clean the parts with carb cleaner. the throttle is the plate located in the intake it gets dirty with sludge, the idle valve if equipped is a cylinder generally black or gray, it lets air bypass the throttle plate it should be near by also. if the maf is the plate type check that the plate moves freely and it is clean, you can clean it with carb cleaner. check everything that has to do with maintenance the spark, cables and fuel filter also.

The spark plugs and ignition wires are probably the exact cause for your problem. After the engine warms up any defect in the ignition wires or spark plug connector will start arcing.

Your Answer

Add photo

Related Questions


Looking for a Used 928 in your area?

CarGurus has 41 nationwide 928 listings and the tools to find you a great deal.


Search Porsche 928 Questions

Porsche 928 Experts

#1 Tom Demyan
Tom Demyan
Reputation 130
#2 MTA1968
Reputation 120
#3 Michael Griffin
Michael Griffin
Reputation 100
View All

Related Models For Sale

Used Porsche 911
105 Great Deals out of 4,488 listings starting at $10,999
Used Porsche 944
97 listings starting at $9,977
Used Chevrolet Corvette
230 Great Deals out of 22,188 listings starting at $3,750
Used Ford Mustang
689 Great Deals out of 44,311 listings starting at $1,500
Used Porsche 924
11 listings
Used Mercedes-Benz SL-Class
42 Great Deals out of 2,722 listings starting at $2,995

Used Cars For Sale

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.